Welcome to the Chair for Molecular Functional Materials. This is a professorship in the context of the cluster of excellence cfaed – “Center for Advancing Electronics Dresden”.
It is headed by Prof. Xinliang Feng.
NBN-Doped Bis-Tetracene and Peri-Tetracene: Synthesis and Characterization
September 14, 2021
The zigzag-edge rich polycyclic aromatic hydrocarbons (PAHs), such as bis-tetracene and peri-tetracene, have attracted increasing attention due to their unique electronic and magnetic properties. However, the instability of bis-tetracene and peri-tetracene caused by the open-shell character limits their further investigations. Thus far, two main strategies, sterically blocking the most reactive position (kinetic stabilization) and heteroatom doping (thermodynamic stabilization), have been established to synthesize stable zigzag-edged higher acenes. Specifically, the introduction of heteroatoms such as boron (B) or nitrogen (N) on the zigzag edges, not only provides access to stable heteroatom-doped acenes but also offers the possibility to tune their electronic structures.
The researchers from the group of Prof. Xinliang Feng in collaboration with the group of Prof. Hong-Jun Gao (Chinese Academy of Sciences) and Dr. Junzhi Liu (The University of Hong Kong) recently demonstrated the synthesis of NBN-doped bis-tetracene (NBN-BT) and peri-tetracene (NBN-PT) through combining solution-based and surface-assisted synthesis methods. Based on the high-resolution STM characterization, NBN-BT adopts a double-helical structure, while NBN-PT displays planar geometry, in which the atomically resolved structure of NBN-PT is further unveiled by nc-AFM characterization. Compared with their carbon-based analogs bis-tetracene (1.56 eV) and peri-tetracene (1.11 eV), the NBN-BT (2.48 eV) and NBN-PT (2.45 eV) exhibit excellent stability under ambient conditions, which is associated with their higher energy gap. Notably, through controlled continuous single-electron chemical or electrochemical oxidation, NBN-BT can be converted into its corresponding radical cation (0.88 eV) and further to dication (1.24 eV), which demonstrates a similar energy gap to its isoelectronic structure bis-tetracene (1.56 eV). This work opens up a new avenue for the synthesis of stable zigzag-edged nanographenes with multi-NBN units and paves the way for investigating the isoelectronic structures of pristine carbon-based zigzag-edged acenes.
Reference: Yubin Fu, Xiao Chang, Huan Yang, Evgenia Dmitrieva, Yixuan Gao, Ji Ma, Li Huang, Junzhi Liu, Hongliang Lu, Zhihai Cheng, Shixuan Du, Hong-Jun Gao, Xinliang Feng. NBN-Doped Bis-Tetracene and Peri-Tetracene: Synthesis and Characterization. Angew. Chem. Int. Ed. 2021, https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202109808
Acknowledgments: This work was supported by the European Union's Horizon 2020 (No 881603 Graphene Flagship Core3, No 813036 Marie Skłodowska-Curie), ERC Grant on T2DCP, German DFG (Cluster of Excellence “Center for Advancing Electronics Dresden (cfaed) and DFG-NSFC Joint Sino-German Research Project (EnhanceNano, No. 391979941), as well as the DFG-SNSF Joint Switzerland-German Research Project (EnhanTopo, No. 429265950). J. Liu is grateful for the funding support from the Hong Kong Research Grants Council (HKU 27301720) and ITC to the SKL. We thank the National Natural Science Foundation of China (Grant Nos. 61888102, and 61674045), the Ministry of Science and Technology (MOST) of China (No. 2019YFA0308500), as well as the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos. XDB30000000). We thank the Center for Information Services and High Performance Computing (ZIH) at TU Dresden for generous allocations of compute resources.
CRC 1415 Summer School “Conductive Metal–Organic Frameworks - From Synthesis to Functions”
September 8, 2021
During the period from September 6 - 8 2021, the Priority Program (PP) 1928 "Coordination Networks: Building Blocks for Functional Systems - COORNETs", Technische Universität München, the Chair of Molecular Functional Materials and the Collaborative Research Centre (CRC) 1415 "Chemistry of Synthetic Two-Dimensional Materials" hosted the virtual Summer School "Conductive Metal-Organic Frameworks - From Synthesis to Functions". The in total 81 participants joined lectures by renowned scientists with focus on the synthesis, characterization and application of conductive metal-organic frameworks (MOFs). In addition, the poster presentations promoted the scientific exchange on further research topics and provided an ideal platform for networking for all participants.
We thank all Summer School participants for their contributions!
Interfacial Synthesis of Layer-Oriented 2D Conjugated Metal–Organic Framework Films toward Directional Charge Transport
August 26, 2021
Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have emerged as a unique class of electronic materials, because they displayed the potential as active layers for electronic devices due to high conductivities (up to 2500 S cm-1) and high carrier mobilities (up to 220 cm2 V-1 s-1) with band-like transport property as well as tunable electronic structures. In the previous reports, a great effort was devoted to exploring electronic properties via the intralayer (basal plane) pathway because it was believed that the high conductivity of 2D c-MOFs depended critically on the full π-electron delocalization in the 2D conjugated plane. However, recent advances demonstrated that long-range charge transport in these layer-stacked framework materials could be primarily mediated via π–π stacking order. Therefore, controlled synthesis of layer-oriented 2D c-MOF films will be highly desirable to direct the charge transport along the interlayer or intralayer pathways and dial-in lateral/vertical electronic devices as well as further unveil the transport mechanism. Nevertheless, such investigations have never been addressed so far due to the challenge in controlling the stacking orientation of 2D c-MOFs in thin films.
The researchers from Prof. Xinliang Feng and Dr. Renhao Dong’s group recently presents the first demonstration of synthesizing unprecedented edge-on layer-orientated p-type semiconducting 2D c-MOF films (Cu2[PcM-O8], M=Cu, Fe) by combining supramolecular chemistry and interface-assisted polymerization. They figure out the crystal structure and orientations of the 2D c-MOFs films with molecular precision, and demonstrate that the edge-on structure formation is guided by the pre-organization of metal-phthalocyanine ligands, whose basal plane is perpendicular to the water surface due to their π-π interaction and hydrophobicity. The synthetic Cu2[PcCu-O8] film features with a thickness of ~20 nm and ~600 nm-sized crystal domains, and exhibits a room temperature conductivity of ~5.6×10-4 S cm-1 and a Hall mobility of ~4.4 cm2 V-1 s-1 based on macroscopic van der Pauw pattern. Lateral and vertical measurements further reveal the directional charge transport feature in this edge-on 2D c-MOF film, i.e., the lateral conductivity is 2~3 orders of magnitude higher than the vertical one. The directional conductivity studies combined with theoretical calculation identify that the intrinsic conductivity of Cu2[PcCu-O8] is dominated by charge transfer along the interlayer pathway.
Reference: Z. Wang, L. S. Walter, M. Wang, P. S. Petkov, B. Liang, H. Qi, N. N. Nguyen, M. Hambsch, H. Zhong, M. Wang, S. Park, L. Renn, K. Watanabe, T. Taniguchi, S. C. B. Mannsfeld, T. Heine, U. Kaiser, S. Zhou, R. T. Weitz, X. Feng, R. Dong, Interfacial Synthesis of Layer-Oriented 2D Conjugated Metal–Organic Framework Films toward Directional Charge Transport, J. Am. Chem. Soc. 2021, https://pubs.acs.org/doi/10.1021/jacs.1c05051
Acknowledgments: This work is financially supported by EU Graphene Flagship (Core3, No. 881603), ERC starting grant (FC2DMOF, No. 852909), ERC Consolidator Grant (T2DCP), DFG projects (SFB-1415, No. 417590517, SPP 1928, WE 4893/6-1, COORNET), H2020-MSCA-ITN (ULTIMATE, No. 813036), as well as the German Science Council and Center of Advancing Electronics Dresden (cfaed). Z.W. gratefully acknowledges funding from the China Scholarship Council. R.T.W. acknowledges funding from the Center for Nanoscience (CeNS) and the Solar Technologies go Hybrid (SolTech) initiative as well as funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy-EXC-2111-390814868 (MCQST) and EXC 2089/1-390776260 (e-conversion). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, A3 Foresight by JSPS, and the CREST (JPMJCR15F3), JST. K.W. and T.T. acknowledge support from the EMEXT Element Strategy Initiative to Form Core Research Center, Grant Number JPMXP0112101001 and the CREST (JPMJCR15F3), JST. P.S.P. and T.H. thank ZIH Dresden for providing high-performance computing facilities. We acknowledge Elettra Sincrotrone Trieste for providing access to its synchrotron radiation facilities and we thank Luisa Barba for assistance in using beamline XRD1. The research leading to this result has been supported by the project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.
Guest Visit Prof. Dr. Klaus Müllen
August 17, 2021
Prof. Dr. Klaus Müllen visited the Collaborative Research Centre (CRC) 1415 from 15th August 2021 to 17th August 2021. A number of principal investigators as well as numerous doctoral students took the opportunity to exchange scientific ideas with Prof. Dr. Klaus Müllen in individual discussions and group meetings.
We deeply thank Prof. Dr. Klaus Müllen for his visit!
COORNET Summer School
August 3, 2021
The program will be directed primarily at PhD students (and advanced Master students) working in the respective COORNETs groups.
Title: Conductive Metal–Organic Frameworks - From Synthesis to Functions
Dates: 6th-8th of September 2021
Location: Online via Zoom
Capacity: ~30 people in person, first come first served basis, please register as soon as possible to ensure your spot!
Lecture/workshop series focusing on conductive MOFs (see attached abstract). We are working on a very exciting speaker list!Networking and poster sessions. This will give the PhD students the chance to get in touch and exchange research topics. Note there is no topic restriction to conductive MOFs here.
Registration: Please send an email to email@example.com with the following details: Name, University, Chair, Contact Email, Attending in person (yes/no). Please only register if you are sure you can attend. Priority (in case of overbooking) will be given to students attending in person.
Fees: All costs will be covered by COORNETs (school program, accommodation, travel).
Corona: While the current situation is promising we will monitor the rules and regulations closely and all planning will be subject to the situation/legislation at the time of the workshop.
Dr. Philip Stanley (TUM)
Dr. Renhao Dong (TUD)
Online Guest lecture - Dr. Holger Meyerheim, Max Planck Institute of Microstructure Physics, Halle
July 26, 2021
Speaker: Dr. Holger Meyerheim, MPI Halle
Date/Time: Friday, July 30, 2021, 4:00 pm - 5:30 pm
Online via Zoom
Online Guest lecture - Prof. Chunyi Zhi, Department of Materials Science & Engineering, City University of Hong Kong, China
July 16, 2021
Speaker: Prof. Chunyi Zhi, City University of Hong Kong, China
Date/Time: Friday, July 15, 2021, 2:00 pm - 3:30 pm
Online via Zoom
Dual Active Sites Conjugated Acetylenic Polymers for Photoelectrochemical Water Reduction in Alkaline Medium
July 15, 2021
Photoelectrochemical (PEC) water splitting is a promising technology for hydrogen production combining the inexhaustible solar energy and the electrolysis of water. A variety of inorganic materials including inorganic metal oxides, transition-metal dichalcogenides and metal sulphides have been reported as photocathodes materials; however, their need of co-catalysts, the high costs and the photocorrosion have been hindered their practical application.
Synthetic organic materials are emerging as an interesting class of photocathodes due to their intrinsic advantages over the inorganic counterparts. These include the broader absorption of the solar spectrum, the molecular tunability of band gaps and energy levels positions and the facile synthesis. So far, they have only been reported under acidic or neutral conditions, facilitated by the high concentration of protons; in alkaline medium, on the other hand, they still show poor performance due to the lack of water dissociation sites, which are needed to produce the required protons.
The researchers from the group of Prof. Xinliang Feng in collaboration with the group of prof. Inez Weidinger (TU Dresden) overcame this issue in the work Thiophene-based Conjugated Acetylenic Polymers with Dual Active Sites for Efficient Co-Catalyst-free Photoelectrochemical Water Reduction in Alkaline Medium, recently published in Angewandte Chemie.
Using a molecular engineering strategy, highly efficient active sites for water dissociation were incorporated in conjugated acetylenic polymers (CAPs) by modifying the polymer skeleton from poly(diethynylthieno[3,2-b]thiophene) (pDET) to poly(2,6-diethynylbenzo[1,2-b:4,5-b’]dithiophene (pBDT) and poly(diethynyldithieno[3,2-b:2’,3’-d]thiophene) (pDTT).
The as-synthesized pDTT and pBDT grown on Cu substrate demonstrated benchmark photocurrent densities of 170 mAcm-2 and 120 mAcm-2 (at 0.3 V vs. RHE; pH 13), which are 4.2 and 3 times higher than that of pDET.
Density Functional Theory (DFT) and electrochemical-operando resonance Raman spectroscopy reported that the Cβ of the outer thiophene rings are the water dissociation active sites, while the diacetylenic linkages function as electrocatalytic active sites. These findings will pave the way to design new and more efficient photocathodes.
Reference: Borrelli, C. J. Querebillo, D. L. Pastoetter, T. Wang, A. Milani, C. Casari, H. K. Ly, F. He, Y. Hou, C. Neumann, A. Turchanin, H. Sun, I. M. Weidinger, X. Feng, Thiophene-based Conjugated Acetylenic Polymers with Dual Active Sites for Efficient Co-Catalyst-free Photoelectrochemical Water Reduction in Alkaline Medium, Angew. Chem. Int. Ed. 2021, 60, 2–8, …/doi/10.1002/anie.202104469
Acknowledgments: This work was financially supported by the Graphene Flagship (GrapheneCore3, No. 881603) and ERC Grant (T2DCP, No. 819698). We acknowledge the cfaed (Center for Advancing Electronics Dresden) and the Dresden Center for Nanoanalysis (DCN) at TU Dresden. I.W. acknowledges the cluster of excellence UniSysCat (EXC 2008/1 -390540038). C.S. and A.M. acknowledge ERC Grant (CoG 2016 EspLORE, No. 724610). A.T. and C.N. acknowledge DFG TRR 234 “CataLight” (B7 and Z2) and research infrastructure grant INST 275/257‐1. M.B. thanks Dr. Tao Zhang, Huanhuan Shi, Dr. Markus Löffler (DCN), and Dr. Zhongquan Liao for preliminary characterization, Dr. Moritz Kuehnel and Dr. Uttam Gupta for preliminary measurements, Dr. Jian Zhang and Dr. Ahiud Morag for fruitful discussions and prof. Fabrizia Negri for preliminary calculations. C.J.Q. acknowledges Markus Göbel for his helpful suggestions.
Synthetic tuning of the quantum properties of open-shell radicaloids
July 13, 2021
Molecular compounds are emerging as appealing units for quantum computation and quantum technologies. For these purposes open-shell molecular radicaloids hold exceptional interest: they offer π-conjugated units with an unpaired electron ground state and they can be considered as atomically-precise pieces of graphene. The next frontier to improve the quantum performance is to determine structure-quantum properties relations, such as how the size of the extended π-systems affects the coherence properties, or how the molecular geometry and electron-nuclear interactions determine the coherence time, so as to channel the synthetic efforts towards blocking decoherence pathways.
The scientists from TU Dresden/Oxford university have established the links between morphology and quantum properties, using three related radicaloids (1, 2 and 3) based on meta-quinodimethane. The roles of the π-conjugated backbone and of the side groups on the spin-flip and quantum coherence times are unraveled. The temperature regions are identified, where different structural parts of the molecule or solvent become the dominant decoherence channel. The record quantum coherence values obtained at room temperature are still well below the intrinsic limits of radicaloids, and the researchers further discuss the directions to optimize the quantum performance. This fruitful work of the joint research has been now published in the renowned journal “Chem” as an article.
Acknowledgments: The authors gratefully acknowledge financial support by the EU Horizon 2020 (ERC-CoG-MMGNRs-773048 and ERC-CoGT2DCP-881603, Graphene Flagship Core3 813036, Marie-Curie program), Royal Society (RS grant and URF), EPSRC (grant no. EP/N509711/1, EP/R042594/1, and EP/L011972/1), German DFG (Cluster of Excellence ‘‘Center for Advancing Electronics Dresden (cfaed)’’) and EnhanceNano-391979941, the European Social Fund and the Federal State of Saxony (ESFProject ‘‘GRAPHD,’’ TU Dresden).
Reference: Fedrico Lombardi, Ji Ma, Hartmut Komber, Dimitris I. Alexandropoulos, Junzhi Liu, William K. Myers, Xinliang Feng, Lapo Bogani, Synthetic Tuning the Quantum Properties of Open-shell Radicaloids, 2021, 7(5), 1363-1378.
Dual-Redox-Sites Enable Two-Dimensional Conjugated Metal–Organic Frameworks with Large Pseudocapacitance and Wide Potential Window
July 13, 2021
Advanced supercapacitor electrodes require the development of materials with dense redox-sites embedded into conductive and porous skeletons. Two-dimensional (2D) conjugated metal-organic frameworks (c-MOFs) are attractive supercapacitor electrode materials due to their high intrinsic electrical conductivities, large specific surface areas, and quasi-one-dimensional aligned pore arrays. However, the reported 2D c-MOFs still suffer from unsatisfying specific capacitances and narrow potential windows because large and redox-inactive building blocks lead to low redox-site densities of 2D c-MOFs.
The researchers from Prof. Xinliang Feng’s group recently demonstrated the dual-redox-site 2D c-MOFs with copper phthalocyanine building blocks linked by metal-bis(iminobenzosemiquinoid) (M2[CuPc(NH)8], M = Ni or Cu), which depict both large specific capacitances and wide potential windows. Experimental results accompanied by theoretical calculations verify that phthalocyanine monomers and metal-bis(iminobenzosemiquinoid) linkages serve as respective redox sites for pseudocapacitive cation (Na+) and anion (SO42-) storage, enabling the continuous Faradaic reactions of M2[CuPc(NH)8] occurring in a large potential window of −0.8 ~ 0.8 V vs. Ag/AgCl (3 M KCl). The decent conductivity (0.8 S m−1) and high active-site density further endow the Ni2[CuPc(NH)8] with a remarkable specific capacitance (400 F g−1 at 0.5 A g−1) and excellent rate capability (183 F g−1 at 20 A g−1). Quasi-solid-state symmetric supercapacitors are further assembled to demonstrate the practical application of Ni2[CuPc(NH)8] electrode, which deliver a state-of-the-art energy density of 51.6 Wh kg−1 and a peak power density of 32.1 kW kg−1. This work provides insightful guidelines for exploring the multielectron Faradaic reactions in new porous framework materials, which will benefit the development of next-generation energy storage technologies.
Reference: Panpan Zhang, Mingchao Wang, Yannan Liu, Sheng Yang, Faxing Wang, Yang Li, Guangbo Chen, Zichao Li, Gang Wang, Minshen Zhu, Renhao Dong, Minghao Yu, Oliver G Schmidt, Xinliang Feng. Dual-Redox-Sites Enable Two-Dimensional Conjugated Metal–Organic Frameworks with Large Pseudocapacitance and Wide Potential Window. J. Am. Chem. Soc. 2021, https://pubs.acs.org/doi/abs/10.1021/jacs.1c03039
Acknowledgments: This work was financially supported by European Union’s Horizon 2020 research and innovation programme (GrapheneCore3 881603), ERC Consolidator grant (T2DCP 819698), ERC Starting grant (FC2DMOF, No. 852909), Deutsche Forschungsgemeinschaft (MX‐OSMOPED), M-ERA.NET and Sächsisches Staatsministerium für Wissenschaft und Kunst (HYSUCAP 100478697), German Research Foundation (DFG) within the Cluster of Excellence, CRC 1415 (grant no. 417590517), Polymer-based Batteries (SPP 2248, RACOF-MMIS), and Coordination Networks: Building Blocks for Functional Systems (SPP1928, COORNETs). We appreciate Dr. Mao Wang for the conductivity measurements and thank Dr. Yulia Krupskaya (IFW Dresden) for EPR measurement. We acknowledge the use of the facilities in Dresden Center for Nanoanalysis at Technische Universität Dresden. The authors thank the Center for Information Services and High Performance Computing (ZIH) at TU Dresden for generous allocations of computer time.
Press Trip Greentech City Dresden
July 8, 2021
The Chair of Molecular Functional Materials, Sixonia Tech GmbH and the Collaborative Research Centre 1415 were pleased to welcome Greentech City Dresden for a short visit on July 8, 2021. The visit of a total of 3 journalists (Sächsische Zeitung, Oiger, IntoVR/Welt) and representatives of the city of Dresden included scientific presentations, demonstrations and interviews.
We thank all participants for their contribution to an exciting press visit!
Online Guest lecture - Kai-Qiang Lin, Department of Physics, University of Regensburg, Germany
June 18, 2021
Speaker: Kai-Qiang Lin, University of Regensburg, Germany
Date/Time: Friday, July 15, 2019, 2:00 pm - 3:30 pm
Online via Zoom
CRC 1415 - Virtual Retreat 2021
May 31, 2021
The consortium of the CRC 1415 organized its first online-based retreat from May 27-28, 2021 with the aim of promoting interaction, communication and teamwork between the members of the CRC 1415.
During two eventful days, the scientific advances in the research areas A (material synthesis), B (characterization) and C (theory) were presented and discussed, taking into account all 22 sub-projects. Furthermore, the retreat participants came together in two virtual poster exhibitions, organized by the doctoral students: inside the Integrated Graduate School 2D Materials (MGK-2DMs). As part of the poster exhibitions, the MGK-2DMs awarded three poster prizes to doctoral students for outstanding performance and presentation inside the CRC 1415. The winners of this years’s MGK-2DMs poster exhibition chosen by the CRC members are: Paula Kalenczuk (1st place), Ankita De (2nd place) and Friedrich Schwotzer (3rd place).
MGK Poster Award Winner
Another highlight of the retreat was the guest lecture by Prof. Cinzia Casiraghi, University of Manchester, Great Britain. Her lecture “Water-based, error-free and biocompatible 2D material inks: From printed devices to biomedical applications” was met with great interest from all participants and we thank Prof. Casiraghi very much for her contribution to the CRC 1415 Retreat 2021!
Guest Lecture Prof. Cinzia Casiraghi
In addition to the scientific exchange, team development and the promotion within the CRC 1415 was not neglected either. An exciting online escape room team event rounded off the evening on the first day of the event. In the Escape Room team event, the CRC members went on a mission together to track down the jewel thief using logical thinking, creativity and communication.
Diamond Fever ©Eplayces
The 2021 retreat concluded with the 3rd General Assembly on the afternoon of May 28th.
Persistent peri-Heptacene: Synthesis and In-Situ Characterization
April 19, 2021
The synthesis of the longest peri-acene, i.e., peri-Heptacene (7-PA) is accomplished by the researchers from the group of Prof. Xinliang Feng in collaboration with Politecnico di Milano, Leibniz Institute for Solid State and Materials Research, and Leibniz-Institut for Polymerforschung Dresden e. V. The work has recently reported as a communication “Persistent peri-Heptacene: Synthesis and In-Situ Characterization” in Angewandte Chemie International Edition. n-peri-Acenes (n-PAs) have gained enormous interest as fundamental model systems of zigzag-edged graphene nanoribbons for the potential applications in synthetic carbon nanoelectronics and spintronics. However, the synthesis of n-PAs larger than peri-tetracene (4-PA) remains challenging because of their intrinsic open-shell character and high reactivity. In this communication, the authors reported the synthesis of the hitherto unknown 7-PA, by a rational molecular design strategy, in which the reactive zigzag edges are kinetically protected with eight 4-tert-butylphenyl groups. The successful formation of 7-PA from its tetrahydro-precursor 3 was clearly validated by high-resolution mass spectrometry and in-situ FT-Raman spectroscopy. The resultant 7-PA displays a narrow optical energy gap of 1.01 eV and exhibits a persistent stability (half-life, t1/2 ~ 25 min) under inert conditions. Moreover, electron spin resonance (ESR) measurements and theoretical studies reveal that 7-PA exhibits an open-shell feature and a significant tetraradical character (y0 = 1.0 and y1 = 0.2). This synthetic strategy could be considered as a modular approach for the construction of next generation (3N+1)-PAs (where N = 3, 4, etc.).
Reference: M. R. Ajayakumar, J. Ma, A. Lucotti, K. S. Schellhammer, G. Serra, E. Dmitrieva, M. Rosenkranz, H. Komber, J. Liu, F. Ortmann, M. Tommasini, and Xinliang Feng, Angew. Chem. Int. Ed. 2021, https://doi.org/10.1002/anie.202102757
Acknowledgments: This research was financially supported by the EU Graphene Flagship (Graphene Core 3, 881603), ERC Consolidator Grant (T2DCP, 819698), the Center for Advancing Electronics Dresden (cfaed) and DFG-NSFC Joint Sino-German Research Project (EnhanceNano, No. 391979941), as well as the DFG-SNSF Joint Switzerland-German Research Project (EnhanTopo, No. 429265950). We thank Mr. Federico Lombardi and Prof. Dr. Lapo Bogani for helpful discussions. The authors acknowledge the use of computational facilities at the Center for information services and high performance computing (ZIH) at TU Dresden. J. Liu is grateful for the startup funding from The University of Hong Kong. G.S. and M.T acknowledge funding by the Italian Ministry of Education, Universities and Research (MIUR) through the PRIN 2017 program (Project No. 2017PJ5XXX “MAGIC DUST”).
A Two-Dimensional Polyimide-Graphene Heterostructure with Ultra-fast Interlayer Charge Transfer
April 15, 2021
The researchers from the group of Prof. Xinliang Feng and Dr. Renhao Dong recently reported the paper “A Two-Dimensional Polyimide-Graphene Heterostructure with Ultra-fast Interlayer Charge Transfer” in Angewandte Chemie International Edition. This is a joint work of TU Dresden, Leibniz-Institut für Polymerforschung Dresden, , Helmholtz-Zentrum Dresden-Rossendorf, and Universität Ulm.
A two-dimensional polymer (2DP) is a sheet-like monomolecular macromolecule consisting of laterally connected repeat units with end groups along all edges. Given the single-atom or -molecule thickness, enormous chemical and structural diversity, 2DPs hold great promise as ideals candidates for van der Waals heterostructures (vdWHs) by stacking different 2D crystals on top of each other. However, the synthesis of 2DP-based vdWHs is still problematic. Firstly, there are tremendous challenges for precisely synthesizing well-defined crystalline monolayer 2DP at molecule level. Secondly, how to realize the transfer and stacking of 2DPs is still unexplored. Thirdly, there should be strong interlayer interaction in vdWH to show new physical properties, which is hard to realize due to the poor long-range ordering of 2DPs.
In recent years, air-water interfacial synthesis is rapidly developing to prepare large-area, free-standing, mono- or few-layer 2DPs, paving the way to synthesize 2DP-based vdWHs. Based on previous work, the research group led by Prof. Feng and Dr Dong used Langmuir–Blodgett technique to synthesize monolayer 2D polyimide (2DPI). Furthermore, the 2DPI film was fabricated with graphene via van der Waals force to prepare a 2DPI-Graphene hybrid material.
Transient absorption (TA) spectroscopy proved that there was ultra-fast (~60 fs) charge transfer from protonated 2DPI to graphene under UV radiation, which can compare with the best records of inorganic vdWH materials. The charge transfer was attributed to the strong cation-π interaction between graphene and protonated 2DP. This work offers an effective strategy for preparing 2DP-based vdWH and discovers a unique charge transfer property due to interfacial electron coupling.
Figure 1. Bottom: A general but reliable on-water synthesis and assembly strategy toward the preparation of 2D polyimide (2DPI)-graphene (G) van der Waals heterostructures (vdWHs) on the water surface is demonstrated. Top: femtosecond transient absorption spectroscopy reveals an ultra-fast interlayer charge transfer (~60 fs) after protonation in the heterostructure, which is among the fastest reports of vdWHs.
Reference: Liu, K., Li, J., Qi, H., Hambsch, M., Rawle, J., Vázquez, A.R., Nia, A.S., Pashkin, A., Schneider, H., Polozij, M., Heine, T., Helm, M., Mannsfeld, S.C.B., Kaiser, U., Dong, R., Feng, X., 2021. A Two‐Dimensional Polyimide‐Graphene Heterostructure with Ultra‐fast Interlayer Charge Transfer. Angewandte Chemie.. doi:10.1002/ange.202102984
Acknowledgments: We acknowledge financial support from EU Graphene Flagship (Core3, No. 881603), ERC Grants on T2DCP and FC2DMOF (No. 852909) and DFG projects (SFB-1415, No. 417590517; SPP 2244, 2DMP) as well as the German Science Council, Centre of Advancing Electronics Dresden, EXC1056 (Center for Advancing Electronics Dresden) and OR 349/1. We thank Prof. Xiaodong Zhuang (Shanghai Jiao Tong University) and Prof. Zhikun Zheng (Sun Yat-sen University) for fruitful discussions. We acknowledge Dresden Center for Nanoanalysis (DCN) for scanning electron microscopy and Dr. Petr Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) for the use of facilities.. We acknowledge Diamond Light Source for time on Beamline I07 under Proposal SI25070.
Vinylene-Linked Two-Dimensional Covalent Organic Frameworks: Synthesis and Functions
March 31, 2021
Two-dimensional conjugated covalent organic frameworks (2D-c-COFs) with covalently bonded repeat units, crystalline and porous frameworks, and in-plane π-conjugations have attracted immense attention. The precise structure and predictable properties of 2D-c-COFs can be applied to specific applications, such as energy storage/conversion, and optoelectronics. In particular, over the last five years, vinylene-linked 2D covalent organic frameworks (V-2D-COFs) have been extensively explored due to their high in-plane π-conjugation and robust nature.
In this Account, we summarized the important developments of V-2D-COFs, from synthetic methods to unique physical properties and functions. For the synthetic methodologies, three reaction methodologies are introduced, including the Knoevenagel-, other aldol-type-, and Horner-Wadsworth-Emmons polycondensations. Afterward, the optoelectronic and magnetic properties of V-2D-COFs are presented. Finally, the promising applications of V-2D-COF, including sensing, photocatalysis, energy storage and conversion are further demonstrated, which demonstrate the merits resulting from the robust vinylene-linked skeleton, full in-plane π-conjugation, and tunable structures.
Reference: Shunqi Xu, Marcus Richter, and Xinliang Feng*. Vinylene-Linked Two-Dimensional Covalent Organic Frameworks: Synthesis and Functions. Acc. Mater. Res. 2021. doi.org/10.1021/accountsmr.1c00017.
Acknowledgments: This work was supported financially by the EU Graphene Flagship (Graphene Core, No. 881603), the Collaborative Research Center (CRC) 1415 “Chemistry of Synthetic Two-Dimensional Materials” (No. 417590517), H2020-MSCA-ITN (ULTIMATE, No. 813036), the Center for Advancing Electronics Dresden (cfaed), and the ERC Consolidator Grant (T2DCP, No. 819698). We thank Dr. Naisa Chandrasekhar, Prof. Bishnu P. Biswal, M. Sc. Dominik Pasoetter and M. Sc. Albrecht Waentig for the helpful discussion.
Prof. Xinliang Feng joins the Max Planck Institute of Microstructure Physics as new Director
March 15, 2021
Prof. Dr. Xinliang Feng will join the Max Planck Institute of Microstructure Physics as a new Director on Monday, March 15, 2021. He will lead the Department of Synthetic Materials and Functional Devices at the Institute.
Prof. Dr. Xinliang Feng will also continue to run the chair for Molecular Functional Materials at TU Dresden.
Prof. Xinliang Feng acted as Guest Editor for the Royal Society of Chemistry's online collection in Nanoscale and Nanoscale Advances
March 15, 2021
Prof. Dr. Xinliang Feng has acted as Guest Editor for the Royal Society of Chemistry's online themed collection in Nanoscale and Nanoscale Advances and contributed articles on the Chemistry of 2D Materials: graphene and beyond.
Dr. Shaygan Nia recently interviewed by EU Graphene Flagship
February 26, 2021
Dr. Shaygan Nia, the Innovation group leader of the chair, was recently interviewed by EU Graphene Flagship and gave his thoughts on the current and potential application of Graphene and 2D materials Foams and Coatings.
Congratulations to Guangbo Chen for successfully defending his PhD
February 17, 2021
Guangbo Chen successfully defended his PhD on “Carbon-rich Nanomaterials for Electrocatalytic Oxygen Reduction Reactions” on February 16, 2021. Congratulations Dr. Chen!
Congratulations to Mingchao Wang for successfully defending his PhD
January 25, 2021
Mingchao Wang successfully defended his PhD on “Phthalocyanine-Based Two-Dimensional Carbon-Rich Conjugated Frameworks” on January 25, 2021. Congratulations Dr. Wang!
Designer Spin Order in Diradical Nanographenes
January 18, 2021
Researchers from the Chair of Molecular Functional Materials of Prof. Xinliang Feng, Technische Universität Dresden, and the research group of Jinfeng Jia, Condensed Matter Physcics, School of Physics and Astronomy Shanghai Jiao Tong University, recently reported the joint paper “Designer Spin Order in Diradical Nanographenes”. The magnetic properties of carbon materials are at the focus of research effort in physics, chemistry and materials science due to their potential applications in spintronics and quantum computing. Although the presence of spins in open-shell nanographenes has recently been confirmed, the ability to control magnetic coupling sign has remained elusive. Here, the researchers demonstrate an effective approach of engineering magnetic ground states in atomically precise open-shell bipartite/nonbipartite nanographenes using combined scanning probe techniques and mean-field Hubbard model calculations. The method provides opportunities for designer above-room-temperature magnetic phases and functionalities in graphene nanomaterials.
Designer Spin Order in Diradical Nanographenes
Yuqiang Zheng, Can Li, Chengyang Xu, Doreen Beyer, Xinlei Yue, Yan Zhao, Guanyong Wang, Dandan Guan, Yaoyi Li, Hao Zheng, Canhua Liu, Junzhi Liu, Xiaoqun Wang, Weidong Luo, Xinliang Feng, Shiyong Wang Jinfeng Jia.
This work was financially supported by the National Natural Science Foundation of China (No. 11874258, 12074247) and Fok Yin Tung foundation. J.L. is grateful for the startup funding from the University of Hong Kong and the funding support from ITC to the SKL. This work is also supported by the Ministry of Science and Technology of China (Grants No. 2016YFA0301003, No. 2016YFA0300403), the National Natural Science Foundation of China (Grants No. 11521404, No. 11634009, No. 11574202, No. 11874256, No. 11790313, No. 11674226, No. U1632102, No. 11674222, No. U1632272 and No. 11861161003), and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB28000000). We acknowledge SJTU HPC center for providing computational resources.
High-Mobility Semiconducting Two-Dimensional Conjugated Covalent Organic Frameworks with p-Type Doping
January 18, 2021
Two-dimensional conjugated covalent organic frameworks (2D c-COFs) have recently emerged as a unique class of 2D conjugated polymers that display high in-plane π-conjugation and weak out-of-plane interactions. Because of their tailorable architectures, abundant active sites, well-defined structures, inherent porosity, chemical stability, and (opto)-electronic properties, these materials are promising for chemiresistors, logic and memory devices, and energy storage. For many of these applications, long-range charge transport is required. Therefore, much effort has been devoted over the last years to interrogate the nature of the conductivity in 2D c-COFs. Recent studies have demonstrated charge carrier mobilities ranging from 5 to 8 cm2/(Vs). Although these mobilities are encouraging, their conductivities have remained rather low (typically <10-6 S/cm). To further improve the conductivity, doping strategies have been employed by incorporating guest molecules that act as dopants, e.g., linear conducting polymers, C60, iodine (I2), etc. For instance, I2-doping has demonstrated improvement of up to 3 orders of magnitude in the conductivities, but this approach was often associated with amorphization/irreversible structural changes of 2D c-COFs. A fundamental understanding of the doping interactions within the lattice in COFs remains largely unexplored.
In order to investigate the role of dopant for 2D c-COFs, researchers from Technical University of Dresden (Chair for Molecular Functional Materials) and collaborators have demonstrated a doping-defined polycrystalline 2D c-COF (ZnPc-pz-I2) through molecular I2-doping of metal-phthalocyanine-based pyrazine-linked 2D c-COF ZnPc-pz. I2-molecules sit preferentially in the COF pores and near the skeleton. Hall effect measurements reveal that doping improves the conductivity and carrier density by approximately 3 and 2 orders of magnitude respectively in ZnPc-pz-I2. Notably, doping also leads to an unprecedented improvement in the Hall charge mobility from ~5 to ~22 cm2/(Vs). Density functional theory (DFT) and time-resolved terahertz spectroscopy (TRTS) show that this record mobility is related to an increase in the scattering time after doping, likely related to the formation of ordered pathways for charge carrier migration between the electron donor (ZnPc-pz) and acceptor (I2) within the framework. Such unique phenomena have never been reported among doped COF materials. This work highlights the potential of developing structurally-defined, doped 2D c-COFs with high conductivity and high mobility, which provides insight on a fundamental understanding of the role of the dopant and the host-dopant interplay necessary to elucidate structure-electronic property relationships.
This work is financially supported from EU Graphene Flagship (GrapheneCore3, No. 881603), ERC Grants (T2DCP and FC2DMOF (No. 852909)), H2020-MSCA-ITN (ULTIMATE, No. 813036), DFG projects (COORNETs, SPP 1928 and CRC 1415, No. 417590517), the German Science Council, Center for Advancing Electronics Dresden (EXC1056), the regional government of Comunidad de Madrid under projects 2017-T1/AMB-5207 & P2018/NMT-4511, as well as the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant No. SEV-2016-0686).
Mingchao Wang, Mao Wang, Hung-Hsuan Lin, Marco Ballabio, Haixia Zhong, Mischa Bonn, Shengqiang Zhou, Thomas Heine, Enrique Cánovas*, Renhao Dong*, Xinliang Feng*. High-Mobility Semiconducting Two-Dimensional Conjugated Covalent Organic Frameworks with p-Type Doping. J. Am. Chem. Soc. 2020, 142, 52, 21622–21627.
Congratulations to SangWook Park for successfully defending his PhD
December 22, 2020
SangWook Park successfully defended his PhD on “Two-Dimensional Organic Framework Films by Amphiphilic Compound Assisted Interfacial Synthesis” on December 16, 2020. Congratulations Dr. Park!
Congratulations to Shunqi Xu for successfully defending his PhD
December 22, 2020
Shunqi Xu successfully defended his PhD on “Cyano-substituted Two-dimensional Sp2-carbon-linked Conjugated Polymers” on December 11, 2020. Congratulations Dr. Xu!
Dr. Chuanhui Huang received the prestigious Humboldt Research Fellowship for Postdoctoral Researchers
December 22, 2020
The Humboldt Research Fellowship is awarded to researchers from abroad with above average qualifications and who are at the beginning of their career. By being granted this fellowship, Dr. Chuanhui Huang, will receive financial support for two years to carry out his research in the research group of Prof. Xinliang Feng and Dr. Renhao Dong at Technische Universität Dresden.
Highly Cited Researcher 2020
December 9, 2020
Prof. Dr. Xinliang Feng has been listed as highly cited researcher in 2020 - in the categories Chemistry and Materials Science - for his research performance demonstrated by the production of multiple highly cited papers that rank in the top 1% by citations for field and year in Web of Science.
Dr. Minghao Yu, research group leader in Prof. Feng's group, has been listed as well as highly cited researcher in 2020 in the category Materials Science.
Former colleagues in the group of Prof. Feng, Dr. Yang Hou and Dr. Xiaodong Zhuang, are also among the highly cited researchers in 2020 in the Cross-Field category.
Ground-breaking Ceremony for New Office and Laboratory Building at TU Dresden
November 25, 2020
l.t.r.: Prof. Ursula M. Staudinger, Dr. Andreas Handschuh, Dr. Volkhard Gürtler. © M. Kretzschmar/TUD
The TU Dresden has started construction work for a new office and laboratory building on Stadtgutstraße, close to the campus. For the first time, the university is also taking over the construction management under its own direction. By August next year, 1,200 square meters of office and lab space will be built. The Chair for Molecular Functional Materials, which is integrated in the Center for Advancing Electronics Dresden (cfaed), as well as the Cluster of Excellence Complexity and Topology in Quantum Matter (ct.qmat) will move in.
"The project is an important step for the further development of our university. Prof. Feng's research group on Molecular Functional Materials and Prof. Ruck's group from the Cluster of Excellence ct.qmat will find optimal conditions for their excellent work here", explains the Rector of TU Dresden, Prof. Ursula M. Staudinger. "The fact that they are moving into a new home together also offers opportunities for even stronger interdisciplinary cooperation in the future," she adds.
Congratulations to Paula Kalenczuk for successfully defending her Master thesis
November 20, 2020
Paula Kalenczuk successfully defended her Master thesis on “Interfacial synthesis of thiophene-based 2D conjugated polymers” on November 20, 2020. Congratulations Paula!
Thiophene‐Bridged Donor–Acceptor sp2-Carbon-Linked 2D Conjugated Polymers as Photocathodes for Water Reduction
November 20, 2020
Figure 1: Scheme for the synthesis of 2D CCP‐HATN-ThDAN and 2D CCP‐HATN-BDAN (left) and imine‐linked 2D C=N HATN-BZD (right) from HATN‐6CHO. Reaction conditions: i) for 2D CCP‐HATN-ThDAN: NEt4OH (0.1 M), dimethylacetamide (DMAc)/ortho‐dichlorobenzene (o‐DCB) = 3/7, 150 °C, 3 days; ii) for 2D CCP‐HATN-BDAN: Cs2CO3 (0.1 M), DMAc/o‐DCB = 1:1, 120 °C, 3 days; iii) for 2D C=N HATN-BZD: DMAc/mesitylene (Mes)/acetic acid (HOAc, 6 m) = 5/5/1, 120 °C, 3 days.
Photoelectrochemical (PEC) water reduction, converting solar energy into environmentally friendly hydrogen fuel, requires delicate design and synthesis of semiconductors with appropriate bandgaps, suitable energy levels of the frontier orbitals, and high intrinsic charge mobility. Two-dimensional covalent organic frameworks (2D COFs), which belong to the class of 2D conjugated polymers, have recently emerged as a promising class of materials for photocatalysis and PEC applications due to the tailored energy bandgaps, positions of the frontier orbitals, and active centers. However, traditional imine‐linked 2D COFs generally exhibit moderate electron delocalization and poor chemical stability, which hamper the potential implementation of these materials in PEC applications.
In this respect, a group of scientists from Technische Universität Dresden (TUD, Chair for Molecular Functional Materials) and collaborators have developed a novel bithiophene-bridged donor-acceptor-based two-dimensional sp2-carbon-linked conjugated polymer (2D CCP). The Knoevenagel polymerization between the electron‐accepting building block 2,3,8,9,14,15‐hexa(4‐formylphenyl) diquinoxalino[2,3‐a:2′,3′‐c]phenazine (HATN‐6CHO) and the first electron‐donating linker 2,2′‐([2,2′‐bithiophene]‐5,5′‐diyl)diacetonitrile (ThDAN) provided the donor-acceptor containing 2D CCP‐HATN-ThDAN with a dual pore structure and high stability. Benefitting from the sp2-carbon-linked framework and donor-acceptor structure, the 2D CCP-HATN-ThDAN exhibited a wide light harvesting range (up to 674 nm), a narrow optical energy gap (2.04 eV), and separated HOMO-LUMO distributions for facilitated charge transfer. When employed as photocathode for PEC water reduction, 2D CCP-HATN-ThDAN presents a superb H2-evolution photocurrent density up to ~7.9 µA cm‑2 at 0 V vs. reversible hydrogen electrode (RHE).
Reference: Shunqi Xu, Hanjun Sun, Matthew Addicoat, Bishnu P. Biswal, Fan He, SangWook Park, Silvia Paasch, Tao Zhang, Wenbo Sheng, Eike Brunner, Yang Hou, Marcus Richter, Xinliang Feng*, “Thiophene‐Bridged Donor–Acceptor sp2‐Carbon‐Linked 2D Conjugated Polymers as Photocathodes for Water Reduction”, Adv. Mater. 2020, 2006274. Link: https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202006274
Acknowledgments: This work was supported financially by the DFG for the CRC 1415 (No. 417590517), the ERC Consolidator Grant (T2DCP, No. 819698), Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET), EU Graphene Flagship (GrapheneCore3; No. 881603), H2020‐MSCA‐ITN (ULTIMATE, No. 813036), and Center of Advancing Electronics Dresden (cfaed).
One-Pot Synthesis of Boron-Doped Polycyclic Aromatic Hydrocarbons via 1,4-Boron Migration
November 20, 2020
Boron-doped polycyclic aromatic hydrocarbons (B-PAHs) are of great current interest due to their excellent photophysical properties and their promising applications in organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs). Although significant efforts have been made in the past few years, the modular synthetic routes toward B-PAHs, particularly for dual-B doped PAHs, remain limited due to the intrinsic instability of B-PAHs against moisture and oxygen. So far, the existing methods for the synthesis of B-PAHs usually involve special precursor design or multiple synthetic steps, e.g., an additional oxidation etc., resulting in low overall yields of synthetic procedures. Thereby, it is highly attractive to develop cost-effective methodologies for the synthesis of B-PAHs from the readily available starting compounds.
Recently, researchers from Technische Universität Dresden (TUD, Chair of Molecular Functional Materials) and collaborators (HKU, Hong Kong) reported a novel one-pot synthetic method toward a series of mono/dual B-PAHs (1a-1o) via an unprecedented 1,4-boron migration process from readily available ortho-aryl substituted arylalkynes. This protocol renders a broad scope of substrates (13 examples) with high atom efficiency and functional group tolerance. The reaction mechanism involves a sequence of borylative cyclization, 1,4-boron migration, and electrophilic C-H borylation. Notably, this is the first example regarding the 1,4-boron migration in the π-conjugated system. Single-crystal X-ray analysis of the represented compounds 1b and 1k demonstrate that the boron atom locates at the zigzag edge and adopts a trigonal planar geometry. The achieved B-PAHs 1a-1o display excellent fluorescence with the photoluminescence (PL) quantum yields (ΦPL) up to 97% in dichloromethane solution (1g) and 91% in the solid-state thin film (1f). As a proof-of-concept study, blue and green OLEDs are fabricated based on B-PAHs 1f and 1k with an external quantum efficiency (EQE) of 3.5% and 3.2%, respectively, demonstrating their promising applications in organic optoelectronic devices.
Reference: Jin-Jiang Zhang, Man Chung Tang, Yubin Fu, Kam-Hung Low, Ji Ma, Lin Yang, Jan J. Weigand, Junzhi Liu,*, Vivian Wing-Wah Yam, Xinliang Feng*.
Acknowledgements: This work was financially supported by the European Union’s Horizon 2020 research and innovation programme (GrapheneCore3 No. 881603, Marie Skłodowska-Curie grant No 813036) ERC T2DCP, the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden (cfaed)” and DFG-NSFC Joint Sino-German Research Project (EnhanceNano), as well as the DFG-SNSF Joint Switzerland-German Research Project (EnhanceTopo). We thank the Center for Information Services and High Performance Computing (ZIH) at TU Dresden for generous allocations of compute resources. J. Liu is grateful for the startup funding from The University of Hong Kong and the funding support from ITC to the SKL.
A curved graphene nanoribbon with multi-edge structure and high intrinsic charge carrier mobility
November 20, 2020
Edge Engineering in Graphene nanoribbons (GNRs)
Both theoretical and experimental studies have demonstrated that the electronic and magnetic properties of GNRs are critically dependent on their widths and edge topologies. In contrast to armchair-edged GNRs (AGNRs) displaying semiconducting property with a direct energy gap, zigzag-edged GNRs (ZGNRs) typically exhibit narrow bandgaps and localized edge states. In addition, cove-edged GNRs with unique curved geometry are attractive because they can exhibit improved dispersibility in solution, and provide an additional means to control the optoelectronic properties of GNRs. Thereby, the combination of armchair, cove, and zigzag edge structures can impart GNRs with unique geometries and physiochemical properties that are not accessible by those with solely one type of edge structures.
The scientists from TU Dresden/SJTU/MPIP have demonstrated that the GNR with combined edge structures of cove, zigzag and armchair, synthesized by the team of Prof. Xinliang Feng in TU Dresden, displayed unique curved geometry, corresponding to an excellent liquid-phase dispersibility. This curved GNR exhibited unprecedented absorption in the near infrared region with a maximum peak at ~850 nm and a particular narrow optical energy gap of ~1.22 eV. The group led by Prof. Misha Bonn in MPIP used ultrafast terahertz spectroscopy to investigate the electronic transport properties of the curved GNR. Terahertz studies revealed the high charge scattering time (~60 fs) and record-high intrinsic charge carrier mobility of ~600 cm2 V-1 s-1 for curved GNR. These results hold great promise for multi-edged curved GNRs in many applications, including photothermal conversion, photovoltaics, and nanoelectronic devices, etc. This fruitful work of the joint research has been now published in the renowned journal “Journal of the American Chemical Society”.
This research is a joint collaboration between scientists from the Technische Universität Dresden (TUD), Shanghai Jiao Tong University (SJTU) and the Max Planck Institute for Polymer Research (MPIP). The authors gratefully acknowledge financial support by the National Natural Science Foundation of China (21774076 and 52073173), Program of Shanghai Academic Research Leader (19XD1421700), Deutsche Forschungsgemeinschaft (DFG) for funding (SFB 858), European Union's Horizon 2020 (No 881603 Gra-phene Flagship Core3, No 813036 Marie Skłodowska-Curie), ERC Grant on T2DCP, German DFG (Cluster of Excellence “Center for Advancing Electronics Dresden (cfaed)” and EnhanceNano (No. 391979941), European Social Fund and the Federal State of Saxony (ESFProject “GRAPHD”, TU Dresden), European Commission in the framework of the ERC Grant NOC2D as well as the startup funding from The University of Hong Kong and the funding support from ITC to the SKL.
Niu, W.; Ma, J.; Soltani, P.; Zheng, W.; Liu, F.; Popov, A. A.; Weigand, J. J.; Komber, H.; Poliani, E.; Casiraghi, C.; Droste, J.; Hansen, M. R.; Osella, S.; Beljonne, D.; Bonn, M.; Wang, H. I.; Feng, X.; Liu, J.; Mai, Y., A Curved Graphene Nanoribbon with Multi-Edge Structure and High Intrinsic Charge Carrier Mobility. JACS, 2020, 142 (43), 18293-18298.
Zn-ion energy storage device: a new application for 2D polyarylimide covalent organic frameworks
November 20, 2020
Zn-ion batteries, utilizing cheap, safe, and high ion-conductive (up to 1 S cm−1) water-based electrolytes, can effectively circumvent the safety and cost issues encountered by non-aqueous Li-ion batteries. The high power density (~5 kW kg−1) and decent energy density (~300 Wh kg−1, in theory) empower Zn-ion batteries to be robust alternatives for grid-scale energy storage devices. However, conventional Zn metal anodes suffer from several intrinsic drawbacks like dendrite growth, side reactions, and use in excess, giving rise to the battery stability concern. Therefore, searching for new anode materials is highly desired to construct reliable Zn-ion energy storage devices.
Recently, researchers from Technische Universität Dresden (Chair of Molecular Functional Materials) demonstrated the first Zn2+-storage anode based on a two-dimensional polyarylimide covalent organic framework (PI-COF) with a high-rate and long-life electrochemical behavior. The electrode is constructed by synthesizing imide-linked PI-COF on carbon nanotubes (CNTs) grown on carbon cloth via a condensation reaction between 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA) and tris (4-aminophenyl) amine (TAPA). Impressively, the obtained PI-COF exhibits a pseudocapacitive Zn2+-storage behavior with a specific capacity of 332 C g−1 (92 mAh g−1) at 0.7 A g−1, a large rate capability (79.8% at 7 A g−1) and a stable cycle life of 85% capacity retention over 4000 cycles. Through in-situ Raman spectroelectrochemistry and DFT calculations, the work also highlights the Zn2+-storage mechanism of the PI-COF electrode to be a two-step redox reaction, which involves the reversible formation of enolates by the stepwise coordination of carbonyl O with Zn2+. Such a favorable anode further enables the assembly of a flexible, high-rate, and dendrite-free full Zn-ion energy storage device. These encouraging results will inspire more efforts devoted to designing new redox-active monomers and fabricating polyarylimide COF structures with higher theoretical specific capacity.
This work was financially supported by European Union’s Horizon 2020 research and innovation programme (GrapheneCore3 881603), ERC Consolidator grant (T2DCP 819698), Deutsche Forschungsgemeinschaft (MX‐OSMOPED), M-ERA.NET and Sächsisches Staatsministerium für Wissenschaft und Kunst (HYSUCAP 100478697), and German Research Foundation (DFG) within the Cluster of Excellence, CRC 1415 (grant no. 417590517), and Polymer-based Batteries (SPP 2248, RACOF-MMIS). The authors acknowledge the use of the facilities in Dresden Center for Nanoanalysis at Technische Universität Dresden. The authors gratefully acknowledge Paderborn Center for Parallel Computing (PC2) and Gauss Centre for Supercomputing e.V. for funding this project by providing computing time on the FPGA-based supercomputer Noctua and the GCS Supercomputer JUWELS at Jülich Supercomputing Centre (JSC).
Minghao Yu, Naisa Chandrasekhar, Ramya Kormath Madam Raghupathy, Khoa Hoang Ly, Haozhe Zhang, Evgenia Dmitrieva, Chaolun Liang, Xihong Lu, Thomas D. Kühne, Hossein Mirhosseini, Inez M. Weidinger, Xinliang Feng*, A High-Rate Two-Dimensional Polyarylimide Covalent Organic Framework Anode for Aqueous Zn-Ion Energy Storage Devices, J. Am. Chem. Soc.,2020.
Congratulations to Kejun Liu for successfully defending his PhD
October 21, 2020
Kejun Liu successfully defended his PhD on “Synthesis of Crystalline Two-Dimensional Polymers on Water Surfaces” on October 5, 2020. Congratulations Dr. Liu!
Synthesis of Vinylene‐Linked Two‐Dimensional Conjugated Polymers via the Horner‐Wadsworth‐Emmons Reaction
September 29, 2020
Interest in linear (1D) conjugated polymers has significantly increased in recent decades due to their semiconducting properties and promising applications in organic optoelectronics. 2D conjugated polymers (2D CPs) consisting of multi-strands of linear conjugated polymers have been the dream of synthetic targets for several decades. The synthesis of 2D CPs with fully vinylene-linked backbones still lacks effective protocols to generate crystalline polymer materials. Vinylene-linked 2D CPs provide high chemical and thermal stabilities as well as complete π-conjugation over the whole 2D polymer framework, making these materials highly attractive for various applications, such as in optoelectronics, spintronics, and energy storage.
To address these synthetic challenges, a group of scientists from Technische Universität Dresden (TUD, Chair for Molecular Functional Materials) and collaborators have developed a novel methodology to synthesize 2D poly(arylenevinylene)s via a Wittig-type reaction (Horner-Wadsworth-Emmons reaction, HWE). The novel vinylene-linked 2D CPs, namely, 2D poly(phenylenequinoxalinevinylene)s 2D-PPQV1 and 2D-PPQV2, were synthesized by employing the HWE reaction between aldehyde- and phosphonate substituted monomers (Figure 1a). Powder X-ray diffraction (PXRD) studies (Figure 1b) and nitrogen adsorption-desorption measurements demonstrate the formation of proclaimed crystalline, dual-pore structures with surface areas of up to 440 m2/g. More importantly, the UV-Vis absorption (Figure 1c) and fluorescence emission (Figure 1d) of the obtained 2D-PPQV1 (Eg=2.2 eV) and 2D-PPQV2 (Eg=2.2 eV) are compared with those of cyano-vinylene-linked 2D-CN-PPQV1 (Eg=2.4 eV) produced by the Knoevenagel reaction and imine-linked 2D COF analog (2D-C=N-PPQV1, Eg=2.3 eV), unambiguously proving the superior conjugation of the vinylene-linked 2D CPs using the HWE reaction.
Figure 1: a) Synthesis of 2D-PPQV1, 2D-PPQV2, 2D-CN-PPQV1, and 2D-C=N-PPQV1; b) PXRD data of 2D-PPQV2: Experimental (black) and Pawley-refined PXRD (red), difference plot (gray), simulated PXRD with AA mismatch stacking (blue), and the model of the simulated eclipsed layer mismatch structure shown in the inset; c) UV-Vis absorption spectra of 2D-C=N-PPQV1 (black), 2D-CN-PPQV1 (red), 2D-PPQV1 (green), and 2D-PPQV2 (blue) (dispersions in 2-propanol, concentration=0.2 mg/mL); d) photographs of the fluorescence emission (λex=365 nm) of 2D-C=N-PPQV1, 2D-CN-PPQV1, 2D-PPQV1, and 2D-PPQV2.
Reference: Dominik L. Pastoetter, Shunqi Xu, Mino Borrelli, Matthew Addicoat, Bishnu P. Biswal, Silvia Paasch, Arezoo Dianat, Heidi Thomas, Reinhard Berger, Sebastian Reineke, Eike Brunner, Gianaurelio Cuniberti, Marcus Richter, Xinliang Feng*. Synthesis of Vinylene‐Linked Two‐Dimensional Conjugated Polymers via the Horner‐Wadsworth‐Emmons Reaction. Angew. Chem. Int. Ed., 2020, DOI: 10.1002/anie.202010398
Acknowledgments: This research was supported financially by the EU Graphene Flagship (GrapheneCore, No. 881603), the Collaborative Research Centre (CRC) 1415 “Chemistry of Synthetic Two-Dimensional Materials” (No. 417590517), H2020-MSCA-ITN (ULTIMATE, No. 813036), the Center for Advancing Electronics Dresden (cfaed), and the ERC Consolidator Grant (T2DCP, No. 819698).
Congratulations to Yubin Fu for successfully defending his PhD
September 24, 2020
Yubin Fu successfully defended his PhD on “Tailor-made Boron, Nitrogen-doped Polycyclic Aromatic Hydrocarbons and Graphene Nanoribbons” on September 21, 2020. Congratulations Dr. Fu!
Congratulations to Jason Melidonie for successfully defending his PhD
September 14, 2020
Jason Melidonie successfully defended his PhD on “Pyrene as Versatile Building Block in PAHs and GNRs” on September 11, 2020. Congratulations Dr. Melidonie!
Seeing is believing: How do grain boundaries look like in 2D Polymers?
August 21, 2020
Since the dawn of Materials Science, researchers in this field have been fascinated by the beauty of crystals, in which all atoms appear at the right position in the right order. But, even the glowing diamonds on the wedding rings, the perfect symbol of eternal love and commitment, are never as perfect as we thought. Crystals, regardless of natural or synthetic, contain defects, where the atoms are not arranged as they are supposed to be or grain boundaries as the borderline between two crystalline domains. The study on the imperfections has been a vital topic in nanomaterials and nanotechnology because even a trivial change in the local structure may bring about substantial variation in materials physical and chemical properties. Since the imperfections can be small as missing tiny atoms are, to see how defects look like, and to establish the connection between defects and the resulting change in the properties belongs to the most challenging tasks ever met by materials scientists. With beginning of this century, just after the revolution in resolution due to the realization of “glasses” for electron microscope’s main lenses, transmission electron microscopy (TEM) became a powerful tool to guide into the world of single atoms. Such modern microscopes can now resolve structural features down to the sub-Angstrom scale (1 Angstrom = 10-10 meter = the order of the size of atoms), and therefore TEM developed now to a close and reliable companion to unravel also two-dimensional (2D) materials starting with graphene, the one carbon atom thin wonder material discovered in 2004 and awarded with the Nobel prize in 2010.
Recent years have witnessed the rise of a new star on the vast sky of synthetic 2D materials, namely, 2D polymer. Contrast to traditional linear polymers discovered 100 years ago by Staudinger (Chem. Ber. 1920, 53, 1073), 2D polymers consist of repeating building blocks in a 2D plane linked by strong covalent bonds, forming a sheet-like network. The enormous chemical and structural diversity of the building blocks (i.e., monomers) and linkage types provide the scientists with a playground filled with infinite creative possibilities. That means the synthetic polymer materials can be pre-designed and 'programmed' for desirable applications.
But, like every other crystalline material, 2D polymers also contain imperfections. Strikingly, how the imperfections really look like remains a mystery till now, even with the best TEMs available. Because TEM uses a high-energy electron beam as the imaging source, whether or not we can image the structure depends not only on the attainable resolution of the microscope. It largely depends also on the material under study itself. Can it remain intact during the imaging process? 2D polymers, unfortunately, like many other organic materials, quickly 'burn to ashes' when the electron beam is switched on. How can we image 2D polymers then? Well, like if you want to read a book in the middle of the night, instead of turning on a surgical light with high brightness, a small candle is probably enough. When translated, we only need to provide just a sufficient amount of electrons to obtain the structural information before the material is destroyed. A simple idea but not easy to realize! A group of scientists from Universität Ulm and Technische Universität Dresden have successfully observed grain boundary structures in 2D polyimine with an unprecedented resolution of 2.3 Angstrom (see Figures 1 and 2). The 2D polyimine was prepared by our recently-developed surfactant-monolayer-assistant interfacial synthesis (SMAIS), which took the synthesis of highly crystalline 2D polymers to a new level. Strikingly, based on the known-knowledge from inorganic 2D materials, such as graphene and transition metal dichalcogenides, high-energy point defects should appear at the grain boundaries between two crystalline domains. However, as demonstrated using our computer simulations, for 2D polymers, the two crystalline domains tend to be connected via flexible covalent bonds at the grain boundaries, suggesting that the local properties of 2D polymers are more robust compared to traditional materials: while in the latter a lot of binding energy is lost due to the imperfection of the bonding between the atoms across the grain boundaries, the structural flexibility of the molecules in the 2D polymer strongly reduces this energy penalty and thus limits the impact of the grain boundary on the stability, but also on the chemical and physical properties of the 2D polymer.
These results are published on August, 14th, 2020 in Science Advances. It makes a fabulous start of the Collaborative Research Centre 1415 "Chemistry of Synthetic Two-Dimensonal Materials".
H. Qi, H. Sahabudeen, B. Liang, M. Položij, M. Addicoat, T. Gorelik, M. Hambsch, M. Mundszinger, S. Park, B. Lotsch, S. Mannsfeld, Z. Zheng, R. Dong, T. Heine, X. Feng, Ute Kaiser, “Near-atomic-scale observation of grain boundaries in a layer-stacked two-dimensional polymer", Sci. Adv. 2020.
H. Sahabudeen and B. Liang contributed equally to this work. H. Qi, T. Heine, X. Feng and U. Kaiser are the corresponding authors of this joint publication.
CSC-Award granted to Dr. Ji Ma
August 11, 2020
Ji Ma, a postdoctoral researcher in the Chair for Molecular Functional Materials, was selected to receive the "2019 Chinese Government Award for Outstanding Self-financed Students Abroad" by the China Scholarship Council. Congratulations!
Dr. Ma received his doctorate degree from Prof. Xinliang Feng’s group at TU Dresden in November of 2019. His PhD study was focused on the Controlled Synthesis of Curved Nanographenes with Tunable Aromaticity. This award recognizes his work for his PhD at Prof. Feng’s group.
The Chinese Government Award for Outstanding Self-financed Students Abroad was established by the China Scholarship Council in 2003 and aims at rewarding the academic excellence of self-financed Chinese students studying overseas. It is considered to be the highest award given by the Chinese government to graduate students studying aboard. Only those with outstanding performance in their PhD studies will be considered by the award panel and no more than 500 young talents will be granted the award each year all over the world.
On-Surface Synthesis of Non-Benzenoid Nanographenes by Oxidative Ring-Closure and Ring-Rearrangement Reactions
August 11, 2020
Figure 1. Synthesis of Non-Benzenoid nanographenes 2A and 2B. Colored rings highlight the formation of heptagons via oxidative ring closure (depicted in green) and cyclodehydrogenation (depicted in blue) and pentalene (2A) and as-indacene (2B) moieties via ring rearrangement (depicted in red).
Nanographenes (NGs) have gained increasing attention due to their immense potential as tailor-made organic materials for nanoelectronics and spintronics. They exhibit a rich spectrum of physicochemical properties that can be tuned by controlling the size or the edge structure or by introducing structural defects in the honeycomb lattice. Moreover, NGs containing unpaired electrons have received increased interest in recent years due to their potential applications in organic spintronics. To date, most reported NGs consist exclusively of benzenoid rings. Nevertheless, the controlled introduction of structural defects, i.e. oddmembered polycycles (pentagons or heptagons), in the honeycomb lattice may have a considerable effect on the physicochemical properties of NGs, arising from local changes in strain and conjugation.
Recently, researchers from Technische Universität Dresden (Chair of Molecular Functional Materials) and collaborators (EMPA, Zurich, and HKU, Hong Kong) reported the design and on-surface synthesis of NGs containing several odd-membered polycycles induced by a thermal procedure on Au(111). Two nonbenzenoid NGs (2A and 2B, Figure 1) containing four embedded azulene units in the polycyclic framework were achieved via onsurface oxidative ring-closure reactions. Interestingly, surface-catalyzed skeletal ring rearrangement reactions in NGs 2A and 2B were observed, which lead to the formation of additional heptagonal rings as well as pentalene and as-indacene units, respectively. The chemical structures of 2A and 2B have been elucidated by STM and nc-AFM. STS studies reveal that 2A and 2B exhibit narrow experimental frontier electronic gaps of 0.96 and 0.85 eV on Au(111), respectively, with moderate open-shell characters. These results reported herein motivate the rational synthesis of larger non-benzenoid ring topologies as functional centers toward the perspective of engineering graphene-based devices.
Thorsten G. Lohr, Jose I. Urgel,* Kristjan Eimre, Junzhi Liu,* Marco Di Giovannantonio, Shantanu Mishra, Reinhard Berger, Pascal Ruffiffiffieux, Carlo A. Pignedoli, Roman Fasel,* and Xinliang Feng.* J. Am. Chem. Soc. 2020, 142, 13565-13572.
This work was supported by the Swiss National Science Foundation (200020_182015), the European Union’s Horizon 2020 research and innovation programme (GrapheneCore2 785219), the Office of Naval Research (N00014-18-1-2708), and the Swiss National Centre for Computational Design and Discovery of Novel Materials (MARVEL). The Swiss National Supercomputing Centre (CSCS) under project ID s746 and s904 is acknowledged for computational resources. The DFGNSFC Joint Sino-German Research Project (EnhanceNano), Center for Advancing Electronics Dresden (cfaed), the European Social Fund, and the Federal State of Saxony (ESF-Project GRAPHD, TU Dresden) are acknowledged for financial support. J.L, is grateful for the startup funding from The University of Hong Kong and the funding support from ITC to the SKL. T.G.L. gratefully acknowledges the International Excellence Graduate School on Emerging Materials and Processes Korea (iEGSEMP Korea) in the context of TU Dresden’s institutional strategy The Synergetic University.
Perspectives on Two-Dimensional Carbon-Rich Conjugated Frameworks for Electrochemical Energy Applications
August 11, 2020
The great success of graphene in electrochemical energy applications (EEAs) has stimulated the recent efforts dedicated to exploring two-dimensional (2D) carbon-rich materials with similar structure features. To this end, 2D carbon-rich conjugated frameworks (2D CCFs), which are built up with atomically ordered planar networks, have been brought into the spotlight. Similar to graphene, 2D CCFs are characterized by high in-plane π-conjugation and weak out-of-plane π-π stacking. The unique structures endow 2D CCFs with regular porosities, large specific surface areas, and superior chemical stability. Especially, 2D CCFs are prepared via bottom-up synthetic strategies, making it convenient to precisely tailor their geometries, catalytic/redox sites, and chemical/physical properties at the molecular level by using modern organic and polymer chemistries. The exploration of 2D CCFs for EEAs has only attracted scientific attention in the last few years. As an emerging research ﬁeld, some critical challenges remain, particularly in establishing an unambiguous correlation between 2D CCF structures and their performances in different EEAs.
Recently, researchers from Technische Universität Dresden (Chair of Molecular Functional Materials) reported their perspectives on the development of 2D CCFs for EEAs. The structural features and synthetic principles of 2D CCFs (including 2D conjugated polymer frameworks and 2D conjugated metal-organic frameworks) are briefly introduced. Recent progress in 2D CCFs designed for diverse energy conversion (electrocatalysis) and storage (supercapacitors and batteries) applications is evaluated. Particular emphasis is put on analyzing the precise structural regulation of 2D CCFs that determines the electrochemical performances. Finally, an outlook is provided for the future development of this field, which concerns novel monomer design, chemical methodology/strategy establishment, and a roadmap toward practical applications.
This work was financially supported by the European Research Council (ERC) Consolidator grant under the European Union’s Horizon 2020 Research and Innovation Programme (T2DCP, grant no. 819698), ERC Starting Grant (FC2DMOF, grant no. 852909), GrapheneCore3 (grant no. 881603), the Deutsche Forschungsgemeinschaft (MX-OSMOPED project), M-ERA.- NET and Sachsisches Staatsministerium fur Wissenschaft und Kunst (HYSUCAP, grant no. 100478697), the German Research Foundation (DFG) within the Cluster of Excellence, CRC 1415 (grant no. 417590517), Polymer-based Batteries (SPP 2248, RACOF-MMIS), and Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET).
Minghao Yu, Renhao Dong, Xinliang Feng*, Two-Dimensional Carbon-Rich Conjugated Frameworks for Electrochemical Energy Applications, J. Am. Chem. Soc. 2020, 142, 12903–12915.
Congratulations to Thorsten Lohr who successfully defended his PhD
July 22, 2020
Thorsten Lohr successfully defended his PhD on “Atomically Precise Synthesis of Nanographenes Based on Pentagons and Heptagons” on July 20, 2020. Congratulations Dr. Lohr!
The SFB 1415 holds its first General Assembly
July 15, 2020
After the Collaborative Research Centre (CRC) 1415 "Chemistry of Synthetic Two-Dimensional Materials" officially started working on July 1, the CRC consortium and numerous guests met on July 14, for its first General Assembly. During the event, research-relevant topics as well as organizational issues have been discussed to enable a fruitful start of the newly established interdisciplinary research initiative.
At the Heinz-Schönfeld lecture hall, Technische Universität Dresden, about 50 participants attended the first General Assembly. The Vice-Rector for Research Prof. Dr. Gerhard Rödel, Technische Universität Dresden, opened the meeting by a speech on behalf of the university. In the further course of the program, the CRC spokesperson Prof. Dr. Xinliang Feng presented the scientific priorities, including future guest researchers, Mercator Fellows and the possibility of supporting the development of excellent young scientist by start-up funds. Moreover, the "Integrated Research Training Group 2D Materials", which is an additional educational framework provided for the doctoral students, was presented by its coordinator Dr. Doreen Beyer.
A BBQ party in a cozy atmosphere completed the General Assembly. We would like to thank all participants for coming!
Guangbo Chen wins the 2020 CGCA Young Researchers Award
July 6, 2020
Guangbo Chen in Prof. Feng's chair at TU Dresden, has recently been honored with one of three ‘Young Researchers Award” from the Chinese-German Chemical Association(CGCA). This award is rewarding the academic excellence of PhD students
studying in Germany in the chemistry and chemical-related fields. On July 5th, Guangbo gave an online presentation on his research topics titled “Engineering Water Dissociation Sites for Enhanced Electrocatalytic Activity”.
CGCA is a non-profit Chinese academic organization of chemistry, chemical engineering and related fields, which composes of members who have experience of studying and working in Germany. The essential goal of CGCA is to promote the academic exchange among its members, as well as to promote cooperation between Chinese and German academic and industrial institutions in chemistry and related fields. CGCA organizes regularly academic meetings and helps its members to participate in various events. See: http://www.gcccd-ev.de/aboutus-EN.php.
Congratulations to Hafeesudeen Sahabudeen who successfully defended his PhD
June 22, 2020
Hafeesudeen Sahabudeen successfully defended his PhD on “Synthesis of structurally defined two-dimensional polymers and their application in energy and electronics” on June 19, 2020. Congratulations Dr. Sahabudeen!
Dr. Renhao Dong received the status of TUD Young Investigator
June 17, 2020
Starting on 25.02.2020, Dr. Renhao Dong has been awarded the status of TUD Young Investigator by the rector of TU Dresden. Congratulations!
Electrochemically exfoliated black phosphorus for osmotic power generation
June 11, 2020
Engineering two-dimensional (2D) membranes has been an effective approach to boost the harvesting of the “blue” osmotic energy between river water and sea water. Black phosphorus (BP), an emerging layered material, has recently been explored for a wide range of ambient applications. However, little attention has been paid to the extraction of the worldwide osmotic energy, despite its large potential as an energy conversion membrane. The researchers from TUD report an experimental investigation of BP membrane in osmotic energy conversion. Through controllable oxidation in water, power output of the BP membrane can be largely enhanced, which can be attributed to the generated charged phosphorus compounds. Depending on the valence of oxidized BP that is associated with oxygen concentration, the power density can be precisely controlled and substantially promoted by ∼220%. Moreover, through constructing a heterostructure with graphene oxide, ion selectivity of the BP membrane increases by ∼80%, contributing to enhanced charge separation efficiency. When mixing natural sea water and river water, the power density can achieve about 4.7 W m-2. This work highlights the large potential of BP in surface-charge-governed aqueous nanofluidic energy devices.
This work was supported by the Alexander von Humboldt Foundation, the European Union’s Horizon 2020 research and innovation program under Grant 881603, the European Science Foundation, and the Coordination Networks: Building Blocks for Functional Systems (SPP1928).
Zhen Zhang, Panpan Zhang, Sheng Yang, Tao Zhang, Markus Löffler, Huanhuan
Shi, Martin R. Lohe and Xinliang Feng*, Oxidation promoted osmotic energy conversion in black phosphorus membranes, PNAS, 2020, DOI: https://doi.org/10.1073/pnas.2003898117.
DFG is funding the Collaborative Research Centre 1415 “Chemistry of Synthetic Two-Dimensional Materials”
June 8, 2020
The economy of the 21st century is enabled and fuelled by advanced materials for electronics and technologies. In this respect, the arena of two-dimensional materials (2DMs) became popular over the last decade, because 2DMs offer great promise in applications ranging from electronic devices to catalysis, and from information technology to medicine. 2DMs represent a class of nanomaterials with single- to few-layers thickness (≤ 10 layers) and high structural definition at the atomic/molecular level.
The Collaborative Research Centre (CRC) 1415 “Chemistry of Synthetic Two-Dimensional Materials” will aim at the controlled bottom-up synthesis and the development of novel classes of synthetic 2DMs with high structural definition. Moreover, the development of in-situ and ex-situ spectroscopic, microscopic and diffraction characterization methods plays a key role. The third focal point of the research initiative is to theoretically tackle the chemical and physical phenomena of 2DMs using advanced theoretical methods and models, and to predict the 2DM’s formation and their physical and chemical properties.
Participating research institutes
Technische Universität Dresden, (cfaed, Professur für Molekulare Funktionsmaterialien)
Leibnitz-Institut für Polymerforschung Dresden e.V.
Leibnitz-Institut für Festkörper- und Werkstoffforschung Dresden
Total funding: ~7.7 Mio. EUR.
Congratulations to Faxing Wang who successfully defended his PhD online
May 29, 2020
Faxing Wang successfully defended his PhD on “Development of Metal-Halogen Batteries with High Energy Densities and Smart Functions” on May 22, 2020. Congratulations Dr. Wang!
ULTIMATE-1st Progress Meeting & Workshop Hosted by TUD (Online Meeting)
May 29, 2020
On May 11th and 12th, the ULTIMATE-1st Progress Meeting & Workshop on how to overcome blackouts & scientific storytelling and ULTIMATE Early-Stage Researchers(ESR)’ presentation took place online, organized by ULTIMATE project and TU Dresden (Dr. Renhao Dong/Prof. Xinliang Feng/Prof. Gianaurelio Cuniberti).
During the workshop Dr. Jane Bormeister gave a vivid and detailed training to let ESRs know how to “catch their audience" via e-presentation, and ESRs from different European institutes presented their background, expertise, research project and the latest results. The purpose of the 1st progress meeting & workshop was to provide techniques of planning, preparation and delivery of clear and high-impact presentations and built collaborations for ESRs.
Synergistic electroreduction of carbon dioxide to carbon monoxide on bimetallic layered conjugated metal-organic frameworks
March 17, 2020
Electrocatalytic carbon dioxide reduction reaction (CO2RR), coupled to renewable energies, offers sustainable opportunities to produce value-added chemicals/fuels. Specifically, electrochemical reduction of CO2 to C1 products (formic acid and CO) is of high relevance for the chemical industry, which can also yield a mixture of CO as carbon-reduced product and H2 as byproduct, which is the components of syngas. However, CO2-to-CO conversion, typically suffers from high kinetic barriers and low selectivity due to the high thermodynamic/kinetic stability of CO2 and the competing hydrogen evolution reaction (HER) in aqueous media, respectively. Despite significant efforts to exploring effective catalysts, the current single site catalysts still fail to meet the requirement of electrochemical syngas synthesis with tunable H2/CO ratio at low overpotential. Therefore, developing highly active and selective electrocatalysts to adjust the competitive reactivity between the CO2RR and HER at room temperature, is imperative.
In order to address these challenges, researchers from Technical University of Dresden (Chair for Molecular Functional Materials) and collaborators have developed a layer-stacked, bimetallic two-dimensional conjugated metal-organic framework (2D c-MOF) with copper-phthalocyanine as ligand (CuN4) and zinc-bis(dihydroxy) complex (ZnO4) as linkage (PcCu-O8-Zn). The PcCu-O8-Zn exhibits high CO selectivity of 88%, turnover frequency of 0.39 s1 and long-term durability (> 10 h), surpassing thus by far reported MOF-based electrocatalysts. The molar H2/CO ratio (1:7 to 4:1) can be tuned by varying metal centers and applied potential, making 2D c-MOFs highly relevant for syngas industry applications. The contrast experiments combined with operando spectroelectrochemistry and theoretical calculation unveil a synergistic catalytic mechanism; ZnO4 complexes act as CO2RR catalytic sites while CuN4 centers promote the protonation of adsorbed CO2 during CO2RR. This work offers a strategy on developing bimetallic MOF electrocatalysts for synergistically catalyzing CO2RR toward syngas synthesis.
Reference: Haixia Zhong, Mahdi Ghorbani-Asl, Khoa Hoang Ly, Jichao Zhang, Jin Ge, Mingchao Wang, Zhongquan Liao, Denys Makarov, Ehrenfried Zschech, Eike Brunner, Inez M. Weidinger, Jian Zhang, Arkady V. Krasheninnikov, Stefan Kaskel, Renhao Dong and Xinliang Feng. Synergistic Electroreduction of Carbon Dioxide to Carbon Monoxide on Bimetallic Layered Conjugated Metal-Organic Frameworks. Nat. commun. 2020, 11, 1409.
This work is financially supported by EU Graphene Flagship (GrapheneCore2 785219) and Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET), as well as the German Science Council and Center of Advancing Electronics Dresden (cfaed). This project also has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (FC2DMOF, grant agreement No. 852909). H.X.Z. gratefully acknowledges funding from the Alexander von Humboldt Foundation. I.M.W. acknowledges the Cluster of Excellence UniSysCat. We acknowledge Dresden Center for Nanoanalysis (DCN) at TUD and Dr. Petr Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) for the use of facilities. We also thank Mr. Zhiyong Wang and Dr. Chongqing Yang for helpful discussions. We thank the beamline scientists at BL14W1 and BL15U1 of the Shanghai Synchrotron Radiation Facility for the XAFS measurements. We thank Mr. Chenbao Lu and Prof. Xiaodong Zhuang for the in-situ XAS electrochemical cell setup, as well as Wei Li for the ex-situ Raman testing. We thank Mr. Zhe Zhang for helping prepare the Au/CP current collector. The computational support from the HZDR computing cluster is gratefully appreciated.
A new vdW gap engineering paradigm enables high-kinetics α-MoO3 anodes for dual-ion energy storage devices
March 17, 2020
Efficient energy storage means storing energy, not only in substantial amounts, but also with significant velocities. However, to date, mitigating the inherent trade-off between energy density and power density remains highly challenging for electrochemical energy storage technologies. Assembling energy storage systems with fast-kinetics ion-intercalation electrodes represents a feasible way, but there is still lack of efficient approaches that remarkably enhance the charge storage kinetics of an ion-intercalation electrode.
Recently, researchers from Technische Universität Dresden (Chair of Molecular Functional Materials) and collaborators (CIRIMAT, France) reported a new paradigm for the van der Waals (vdW) gap engineering of α-MoO3. H2O molecules were incorporated into the vdW interlayers of α-MoO3 by taking the place of lattice O in α-MoO3, which further induced an exceptional vdW gap expansion with b-lattice parameter increased by 1.2 Å. The incorporated H2O molecules can not only function as effective spacers to stabilize the expanded interlayer gaps of α-MoO3, but also shield the strong electrostatic interaction between Li+ and α-MoO3 lattice, thus providing efficient Li+ diffusion channels and alleviating the volume change of e-MoO3 during repeated Li intercalation/de-intercalation. These properties further empowered the modified α-MoO3 as a high-rate, long-life, and reliable anode for dual-ion-intercalation energy storage (DIES) devices. The as-assembled MoO3//graphite DIES device can operate within a 1.0 ~ 3.5 V voltage window over a wide discharge rate range (discharge time from 25 s to 3.5 h), and show high energy density (device-level 44 Wh L−1) with decent power capability (600 W L−1).
This work was financially supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 819698 and GrapheneCore2 785219), Deutsche Forschungsgemeinschaft (MX‐OSMOPED project), and German Research Foundation (DFG) within the Cluster of Excellence. H. Shao, P. Rozier, and P. Simon thank the Agence Nationale de la Recherche (Label STORE-EX) for financial support. The authors acknowledge the use of the facilities in the Dresden Center for Nanoanalysis at the Technische Universität Dresden and synchrotron experimental facilities of the National Synchrotron Radiation Laboratory (NSRL) in Hefei, China (BL10B beamline).
Minghao Yu, Hui Shao, Gang Wang, Fan Yang, Chaolun Liang, Patrick Rozier, Cai-Zhuang Wang, Xihong Lu, Patrice Simon* & Xinliang Feng*, Interlayer gap widened α-phase molybdenum trioxide as high-rate anodes for dual-ion-intercalation energy storage devices, Nat. Commun., 2020, 11, 1348.
The M-ERA-NET 2019 proposal coordinated by Chair of Molecular Functional Materials has been granted
March 9, 2020
The project “Synthesis and characterization of novel 2D hybrid materials for supercapacitors, HYSUCAP” has been granted from M-ERA-NET 2019 call. This project is a collaboration between Brno University of Technology, Czech Republic, University of Warsaw, Poland and Technische Universität Dresden and will be coordinated by Chair of Molecular Functional Materials. Within this project novel hybrid 2D materials will be synthesized, characterized and used for fabrication of energy storage devices such as supercapacitors.
Functional two-dimensional polymers enabled by interfacial synthesis
March 2, 2020
Two-dimensional covalent organic frameworks (2D COFs) or layer-stacked 2D polymers, as rising organic 2D materials, have been enormously developed via reversible covalent reactions by solvothermal synthesis method, and have exhibited great potential as activesemiconducting layers for (opto-)electronics. However, since solvothermal synthesis of organic crystals is inclined toward to poorly controlled nucleation and aggregation, the resultant 2D COFs are usually in the form of polycrystalline powders. Therefore, incorporation of these insoluble 2D COF powders into thin film logic and memory devices represents a formidable challenge due to the difficulty in thin-film processability and device integration associated with the necessity of controlling film thickness, layer orientation, stability and crystallinity.
Left : Imine-based 2D COF/polymer and its semiconducting property
Right : Boronate ester-based 2D COF/polymer and its neuromorphic memory device application
To address these synthetic and application challenges, a group of scientists from Technische Universität Dresden (TUD, Chair for Molecular Functional Materials) and collaborators have developed novel synthesis of large-area, free-standing, crystalline, few-layer 2D COF/polymer films utilizing a surfactant-monolayer-assisted interfacial synthesis (SMAIS) method on water surface for opening up exciting opportunity for the integration of 2D polymers into devices and systems. Mr. Hafeesudeen Sahabudeen synthesized three polycrystalline multilayer imine-based 2D COF/polymer films with tunable thickness from 6 to 200 nm via SMAIS method and unveiled the crystalline structures at the molecular lever by HRTEM in close collaboration with Prof. Ute Kaiser (Uni Ulm). The achieved crystalline 2D COF/polymer film with in-plane orientation exhibits a transient mobility as high as 0.01 cm2V-1s-1 as characterized by THz spectroscopy in collaboration with Prof. Mischa Bonn (MPIP) and Prof. Enrique Cánovas (IMDEANanociencia). This work establishes the clear structure-transport property relationship, which is a significant step for the development of semiconducting 2D COFs/polymers as well as their future FET device integration. To further explore the crystallinity and thin-film processability of 2D COF/polymer films, Mr. SangWook Park synthesized boronate ester-based 2D COF/polymer thin films with the single crystalline domains as large as ~60 μm2, which is a record to those of reported 2D COF films. Due to the high crystallinity, facile thin-film processability, high mechanical stability as well as the incorporation of electroactive porphyrin monomers, in collaboration with Prof. Gianaurelio Cuniberti (TUD), the developed few-layer 2D COF/polymer film was for the first time integrated into an organic thin film/Silicon nanowire-based field-effect transistor to mimic neuronal synapses, displaying a learning-erasing-forgetting memory process. This work broadens the interfacial synthesis of highly crystalline, few-layer 2D COF/polymer thin films and opens up a new area for developing such emergent materials as active components in memory devices for future neuromorphic computing, which also provides possibilities for the future development of COF-based flexible and wearable logic and memory electronics.
- Hafeesudeen Sahabudeen#, Haoyuan Qi#, Marco Ballabio, Miroslav Položij, Selina Olthof, Rishi Shivhare, Yu Jing, SangWook Park, Kejun Liu, Tao Zhang, Ji Ma, Bernd Rellinghaus, Stefan Mannsfeld, Thomas Heine, Mischa Bonn, Enrique Cánovas, Zhikun Zheng,* Ute Kaiser,* Renhao Dong,* Xinliang Feng*. Highly Crystalline and Semiconducting Imine-Based Two-Dimensional Polymers Enabled by Interfacial Synthesis. Angew. Chem. Int. Ed. 2020, DOI: 10.1002/anie.201915217.
- SangWook Park, Zhongquan Liao, Bergoi Ibarlucea, HaoyuanQi, Hung-Hsuan Lin, Daniel Becker, Jason Melidonie, TaoZhang, Hafeesudeen Sahabudeen, Larysa Baraban, Chang-Ki Baek, Zhikun Zheng, Ehrenfried Zschech, Andreas Fery, Thomas Heine, Ute Kaiser, Gianaurelio Cuniberti, Renhao Dong,* Xinliang Feng*. Two-Dimensional Boronate Ester Covalent Organic Framework Thin Films with Large Single Crystalline Domains for Neuromorphic Memory Device. Angew. Chem. Int. Ed. 2020, DOI: 10.1002/ange.201916595.
This work was financially supported by Graphene Flagship (Core 3), ERC Grants on T2DCP and FC2DMOF (grant agreement No. 852909) and COORNET (SPP 1928) as well as the German Science Council and Centre of Advancing Electronics Dresden, EXC1056, (cfaed)and OR 349/1. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement 785219. Dr. Haoyuan Qi. and Prof. Ute Kaiser thank the financial support by the DFG in the framework of the “SALVE” (Sub‐Angstrom Low‐Voltage Electron Microscopy) project as well the Ministry of Science, Research and the Arts (MWK) of Baden‐Wuerttemberg in the framework of the SALVE project. Prof. Zhikun Zheng thanks financial support from the National Natural Science Foundation of China (51873236).We thank Dresden Center for Nanoanalysis (DCN) at TUD and Dr. Petr Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) and Christine Damm (IFW) for the use of facilities. GIWAXS was carried out at DESY, a member of the Helmholtz Association (HGF), and at Helmholtz‐Zentrum Berlin. We would like to thank M. Schwartzkopf for assistance (P03‐MINAXS beamline) and Dr. Daniel Többens (KMC‐2 beamline). We thank HGF and HZB for the allocation of neutron/synchrotron radiation beamtime and ZIH Dresden for computer time.We gratefully acknowledge the International Excellence Graduate School on Emerging Materials and Processes Korea (iEGSEMP Korea) in the context of TU Dresden Institutional Strategy The Synergetic University.
Congratulations to Doreen Beyer who successfully defended her PhD
December 13, 2019
Doreen Beyer successfully defended her PhD on “Challenging Edges: Bottom-up Synthesis of Nanographenes Comprising a Zigzag-Edged Periphery” on December 6, 2019. Congratulations Dr. Beyer!
Congratulations to Marcus Richter who successfully defended his PhD
December 13, 2019
Marcus Richter successfully defended his PhD on “Polycyclic Aromatic Azomethine Ylides as Versatile Building Blocks for Unprecedented N-Containing Polycyclic Aromatic Hydrocarbons” on December 6, 2019. Congratulations Dr. Richter!
Topological Frustration Induces Unconventional Magnetism in a Nanographene
December 11, 2019
Finite-sized graphene molecules comprising identical hexagonal rings in one plane are so-called nanographenes (NGs), which show dependence of the intrinsic electronic structure on the topologies of the edge bonds and the π-electron network. In 1972, Erich Clar envisioned the Clar’s Goblet, a D2h-symmetric nanographene with a concealed non-Kekulé structure and two unpaired electrons, creating a magnetically non-trivial ground state.
Very recently, researchers from the Technische Universität Dresden (Chair of Molecular Functional Materials) and collaborators (EMPA, Zurich, Switzerland) with expertise in on-surface physics and chemistry reported the first experimental realization of the Clar’s Goblet via combined in-solution and on-surface synthesis. Subsequent low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) reveal an antiferromagnetic intrinsic property with a large exchange coupling of 23 meV when the Clar’s Goblet is adsorbed on the gold surface. Furthermore, switching of the magnetic ground state by atomic manipulation provides direct evidence of carbon magnetism in the simple, bow-tie shaped nanographene.
“Topological frustration induces unconventional magnetism in a nanographene”
Shantanu Mishra, Doreen Beyer, Kristjan Eimre, Shawulienu Kezilebieke, Reinhard Berger, Oliver Gröning, Carlo A. Pignedoli, Klaus Müllen, Peter Liljeroth, Pascal Ruffieux, Xinliang Feng, Roman Fasel
This work was financially supported by the Swiss National Science Foundation (grant nos 200020-182015 and IZLCZ2-170184), the NCCR MARVEL funded by the Swiss National Science Foundation (grant no. 51NF40-182892), the European Union’s Horizon 2020 research and innovation programme under grant agreement nos 696656 and 785219 (Graphene Flagship Core 2), the Office of Naval Research (N00014-18-1-2708), ERC Consolidator grant (T2DCP, no. 819698), the German Research Foundation (DFG) within the Cluster of Excellence Center for Advancing Electronics Dresden (cfaed) and EnhanceNano (no. 391979941), and the European Social Fund and the Federal State of Saxony (ESF-Project GRAPHD, TU Dresden). We acknowledge computational support from the Swiss Supercomputing Center (CSCS) under project ID s904; S. K. and P. L. acknowledge funding from the Academy of Finland (grant nos 309975 and 318995) and the European Research Council (ERC-AdG no. 788185) and the facilities of the Aalto Nanomicroscopy Centre.
Congratulations to Ji Ma who successfully defended his PhD
December 5, 2019
Ji Ma successfully defended his PhD on “Controlled Synthesis of Curved Nanographenes with Tunable Aromaticity” on November 29, 2019. Congratulations Dr. Ma!
Quantum units from the topological engineering of molecular graphenoids
December 4, 2019
Controlling quantum defects in graphene
Robustly coherent spin centers that can be integrated into devices are a key ingredient of quantum technologies. Vacancies in semiconductors are excellent candidates, and theory predicts that defects in conjugated carbon materials should also display long coherence times. However, the quantum performance of carbon nanostructures has remained stunted by an inability to alter the sp2 -carbon lattice with atomic precision.
The scientists from Oxford University/TU Dresden/MPIP have demonstrated that topological tailoring leads to superior quantum performance in molecular graphene nanostructures, which opens completely new perspectives for graphene spintronics. The saddle-shaped polycyclic hydrocarbon, synthesized by the team of Prof. Xinliang Feng in TU Dresden, possesses an open-shell singlet biradical structure in the ground state and exhibits high stability under ambient conditions (t1/2=39 days). The group led by Prof. Lapo Bogani in Oxford University used the pulsed electron paramagnetic resonance to investigate the quantum properties of this interesting biradicaloid. The decoherence mechanisms, quantify nuclear and environmental effects were clearly unraveled, and large spin-coherence times (Tm) were observed that outclass most nanomaterials. These results validate long-standing assumptions on the coherent behavior of topological defects in graphene and open up the possibility of introducing controlled quantum-coherent centers in the upcoming generation of carbon-based optoelectronic, electronic, and bioactive systems. This fruitful results of the joint research have been now published in the renowned journal “Science”.
This research is a joint collaboration between scientists from the Oxford University, Technische Universität Dresden and the Max Planck Institute for Polymer Research (MPIP). The authors gratefully acknowledge financial support by the European Union (ERC-StG-338258- OptoQMol, ERC-CoG-773048-MMGNRs, ERC-CoG-819698-T2DCP, Graphene Flagship-Core2-696656, and European Social Fund); the Royal Society (University Research Fellow and URF grant); UKEPSRC EP/L011972/1; German DFG (Excellence Cluster CFAED and EnhanceNano-391979941); and the Max Planck Gesellschaft and Saxony ESF-Project-GRAPHD.
Federico Lombardi, Alessandro Lodi, Ji Ma, Junzhi Liu, Michael Slota, Akimitsu Narita, William K. Myers, Klaus Müllen, Xinliang Feng, Lapo Bogani. Quantum units from the topological engineering of molecular graphenoids. Science 2019, 366 (6469), 1107-1110.
A perspective review in Science magazine by Prof. Feng and his colleagues about the future of Energy Storage
December 2, 2019
The recent open access review article about nanomaterials for energy storage published in Science magazine. https://science.sciencemag.org/content/366/6468/eaan8285
This work is the collaboration between Prof. Xinliang Feng from the Chair Molecular functional material in TU Dresden and other top scientist including “Prof. Gogotsi & Prof. Pomerantseva from Drexel university USA”, “Dr. Bonaccorso from Italian Institute of technology” and “Prof. Cui from Stanford University, USA”. This article is a future-oriented perspective rather than a conventional literature review about application of nanomaterials for future of energy storage in different area of applications from mobile phones to electronic vehicles and grids.
It is important to mention that in limelight of EU and German government policies for decarbonization of society, the chair of molecular functional materials in TU Dresden investing a lot of effort for developing new materials especially 2D materials for high energy and efficient energy storage devices such as battery and supercapacitor.
EU Graphene Flagship Meetings took place at TUD in November 2019
November 28, 2019
On November 11th and 12th two meetings of the EU Graphene Flagship with more than 30 participants from different European institutes and companies took place at TU Dresden. The chair for molecular functional materials (Prof. Xinliang Feng) is the leader of Working Package 13 (Functional Foams and Coatings) and Spearhead Project 6 (WearGraph, Self-powered graphene-based textile for wearable electronics) of the EU Flagship project. The purpose of these meetings was to discuss the results and prepare the prototypes in the field of wearable electronics, energy storage and water purification based on graphene and 2D materials.
TUD Professors from the Chemistry Faculty visited Shanghai and Beijing in October 2019
November 11, 2019
At the end of October 2019, Prof. Feng had invited Prof. Heine, Prof. Ruck and Prof. Weigand to visit the universities of Shanghai and Beijing in order to expand the discussions and future cooperations between these institutions.
Guest lecture - Prof. Lei Jiang, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P.R. China
October 28, 2019
Speaker: Prof. Lei Jiang, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P.R. China
Date/Time: Friday, November 1, 2019, 4:00 pm - 5:00 pm
Location: TU Dresden, Chemie-Neubau (CHE), lecture hall CHE 089 (ground floor), Bergstrasse 66, 01069 Dresden
Topic: “Smart Interfacial Materials with Super-Wettability”
Unveiling Electronic Properties in Metal-Phthalocyanine-based Pyrazine-linked Conjugated Two-Dimensional Covalent Organic Frameworks
Published on October 21, 2019
Conjugated two-dimensional (2D) covalent organic frameworks (COFs), also termed as 2D conjugated polymer frameworks, have also been rising as active semiconductors for potential applications in optoelectronics, photovoltaics, chemiresistive sensing, and (photo)electrocatalysis. To date, improved electronic properties in π-conjugated 2D COFs have been achieved by systematic engineering of the framework favoring extended conjugation, e.g., by employing conjugated linkers such as carbon-carbon bonds and pyrazine units. Besides conjugated linkers, planar conjugated building blocks such as pyrene, porphyrin, hexabenzocoronene and phthalocyanine have been employed with the aim of improving mobilities. Although the recent developments illustrate that improved charge transport properties are at reach by rational tuning of COF structures, current approaches are generally unable to establish a neat relationship between the structure and electronic properties. To do so, a thorough analysis of intrinsic and extrinsic factors affecting the charge transport is highly required for π-conjugated 2D COFs where differential analysis is feasible (i.e., where changes in composition are not dramatically affecting the energy band diagram).
In order to address these challenges, researchers from Technical University of Dresden (Chair for Molecular Functional Materials) and collaborators have developed two novel pyrazine (pz)-linked metal-phthalocyanine (MPc)-based conjugated 2D COFs (MPc-pz, M = Zn or Cu), which assembled as van der Waals (vdWs) layer-stacked structures. The resultant materials are found to be polycrystalline p-type semiconductors with band gaps of ~1.2 eV. Van der Pauw, Hall effect, time-resolved terahertz spectroscopy (TRTS), and density functional theory (DFT) calculations are employed for characterizing univocally the intrinsic and extrinsic factors determining the electronic properties of these materials. We demonstrate that for this p-type semiconductor changing the metal center from Cu to Zn in the phthalocyanine moiety has a negligible effect in the conductivity, charge density, charge carrier scattering rate, and effective mass of majority carriers (holes). Mobilities up to ~5 cm2/(Vs) are resolved in the dc limit, which is limited by long-range charge carrier transport across crystalline grain boundaries. Interestingly, charge transport is found to be highly anisotropic, with hole mobilities being practically null in-plane and finite out-of-plane for the developed 2D COFs.
This work is financially supported from EU Graphene Flagship, ERC Consolidator Grant (T2DCP), Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET) as well as the German Science Council, Center of Advancing Electronics Dresden, EXC1056, (cfaed) and OR 349/1. We acknowledge Dresden Center for Nanoanalysis (DCN) at TUD; Dr. Philipp Schlender, Dr. Konrad Schneider (Leibniz Institute for Polymer Research, IPF, Dresden), Dr. Tilo Lübken and Mr. Friedrich Schwotzer for the use of facilities. We also appreciate Mr. Ji Ma, Dr. Haixia Zhong, and Ms. Yu Zhang (UvA) for the MS, SEM and XPS analysis, respectively. We thank Mr. Chi Xu (HZDR), Dr. Chongqing Yang and Dr. Zhongquan Liao (IKTS) for the helpful discussions. Prof. T. Heine and Hung-Hsuan Lin acknowledge the Centre for Information Services and High-Performance Computing (ZIH) in Dresden, Germany for the provided computational resources.
Mingchao Wang, Marco Ballabio, Mao Wang, Hung-Hsuan Lin, Bishnu P. Biswal, Xiaocang Han, Silvia Paasch, Eike Brunner, Pan Liu, Mingwei Chen, Mischa Bonn, Thomas Heine, Shengqiang Zhou, Enrique Cánovas*, Renhao Dong*, Xinliang Feng*. Unveiling Electronic Properties in Metal-Phthalocyanine-based Pyrazine-linked Conjugated Two-Dimensional Covalent Organic Frameworks. J. Am. Chem. Soc.2019, DOI: 10.1021/jacs.9b07644.
Visit of TUD Delegation at Shanghai Jiao Tong University and Tongji University promises fruitful future cooperation
October 9, 2019
At the end of September, we had a wonderful trip to Shanghai accompanied by TU Dresden Rector Prof. Müller-Steinhagen, Prorector Prof. Krauthäuser and Prof. Gianaurelio Cuniberti. We successfully built up strategic cooperations with Shanghai Jiao Tong University and Tongji University which are among the top Chinese universities. We look forward to the next steps!
Bottom-up Synthesis of Crystalline 2D Polymers: A Dream Finally Comes True
Published on September 24, 2019
Left: Schematic illustration for the SMAIS method for 2D polymer synthesis (by Marc Hermann, TRICKLABOR).
Right: High-resolution transmission electron microscopic image for 2D polyimide (by Dr. Haoyuan Qi, Uni Ulm)
Scientists at the Center for Advancing Electronics Dresden (cfaed) at TU Dresden have succeeded in synthesizing sheet-like 2D polymers by a bottom-up process for the first time. A novel synthetic reaction route was developed for this purpose. The 2D polymers consist of only a few single atomic layers and, due to their very special properties, are a promising material for use in electronic components and systems of a new generation. The research result is a collaborative work of several groups at TU Dresden and the University of Ulm and was published this week in two related articles in the scientific journals "Nature Chemistry" and "Nature Communications".
Ever since Hermann Staudinger discovered the linear polymers in 1920, it has been a dream of synthetic scientists to extend the polymerization into the second dimension. A two-dimensional (2D) polymer is a sheet-like monomolecular macromolecule consisting of laterally connected repeat units with end groups along all edges. Given the enormous chemical and structural diversity of the building blocks (i.e., monomers), 2D polymers hold great promise in the rational material design tailored for next-generation applications, such as membrane separation, electronics, optical devices, energy storage and conversion, etc. However, despite the tremendous developments in synthetic chemistry over the last century, the bottom-up synthesis of 2D polymers with defined structures remains a formidable task.
Since 2014, a group of scientists from Technische Universität Dresden and Universität Ulm joined forces to pursue this intriguing yet challenging goal. The research team led by Prof. Dr. Xinliang Feng (TU Dresden) innovatively developed a novel synthetic route: using surfactant monolayer as a soft template to guide the supramolecular organization of monomers and the subsequent 2D polymerization at an air-water interface. This synthetic methodology is now termed as surfactant-monolayer-assistant interfacial synthesis (SMAIS). By using the SMAIS method, Dr. Tao Zhang synthesized crystalline quasi-2D polyaniline films with lateral size ~50 cm2 and tunable thickness (2.6 - 30 nm). The superior charge transport properties and chemiresistivity toward ammonia and volatile organic compounds render the quasi-2D polyaniline films as promising electroactive materials for thin-film organic electronics. To further explore the potential of SMAIS, Mr. Kejun Liu, Dr. Tao Zhang, Dr. Zhikun Zheng and Dr. Renhao Dong achieved controlled synthesis of highly-crystalline few-layer 2D polyimide and polyamide for the first time. The 2D polymers have a thickness of only a few nanometers and can be readily transferred onto arbitrary substrates, opening up exciting opportunity for the integration of 2D polymers into next-generation devices and systems.
Along with the pivotal developments on the synthesis front, the transmission electron microscopy group led by Prof. Dr. Ute Kaiser (Uni Ulm) provided another indispensable pillar of the joint research. Since the development of aberration correction, high-resolution TEM imaging has been a powerful technique in structural characterization down to the atomic scale. Yet, hydrogen-containing organic materials are extremely prone to structural disintegration under the electron beam, rendering HRTEM imaging of 2D polymers a highly demanding mission. By utilizing the spherical-aberration-corrected HRTEM, Dr. Haoyuan Qi has successfully unraveled the micro-morphology, molecular structures, grain boundary and edge structures, of the synthetic 2D polymers: an achievement which is rarely reported in literature.
The molecular structures and overall crystallinity have been further elucidated via synchrotron grazing-incidence X-ray scattering (cfaed Chair for Organic Devices, Prof. Dr. Stefan Mannsfeld, TU Dresden). The group of Prof. Dr. Thomas Heine (TU Dresden) provided density-functional tight-binding calculations which offers significant insights into the atomistic structures of the synthetic 2D polymers.
This fruitful results of the joint research have been published this week on Nature Chemistry (DOI: 10.1038/s41557-019-0327-5) and Nature Communications (DOI: 10.1038/s41467-019-11921-3) in tandem.
The authors gratefully acknowledge financial support by ERC Grant on T2DCP and EU Graphene Flagship, COORNET (SPP 1928), CONJUGATION-706082 as well as the German Science Council, Centre of Advancing Electronics Dresden, EXC1056, (cfaed) and OR 349/1. Haoyuan Qi and Ute Kaiser thank the financial support by the DFG in the framework of the “SALVE” (Sub-Angstrom Low-Voltage Electron Microscopy) project as well the Ministry of Science, Research and the Arts (MWK) of Baden-Wuerttemberg in the framework of the SALVE project. Kejun Liu thanks the China Scholarship Council (CSC) for the financial support.
- Kejun Liu, Dr. Haoyuan Qi, Dr. Renhao Dong, Rishi Shivhare, Dr. Matthew Addicoat, Dr. Tao Zhang, Hafeesudeen Sahabudeen, Prof. Thomas Heine, Prof. Stefan Mannsfeld, Prof. Ute Kaiser, Prof. Zhikun Zheng, Prof. Xinliang Feng. On-water surface synthesis of crystalline two-dimensional polymers assisted by surfactant monolayers. Nature Chemistry (2019). DOI: 1038/s41557-019-0327-5.
- Tao Zhang , Dr. Haoyuan Qi , Dr. Zhongquan Liao , Yehu Horev , Luis Panes-Ruiz , Dr. Petko Petkov , Zhe Zhang , Rishi Shivhare, Panpan Zhang, Kejun Liu, Viktor Bezugly , Prof. Shaohua Liu , Prof. Zhikun Zheng , Prof. Stefan Mannsfeld , Prof. Thomas Heine , Prof. Gianaurelio Cuniberti , Prof. Hossam Haick , Prof. Ehrenfried Zschech , Prof. Ute Kaiser, Dr. Renhao Dong, Prof. Xinliang Feng. Engineering Crystalline Quasi-Two-Dimensional Polyaniline Thin Film with Enhanced Electrical and Chemiresistive Sensing Performances. Nature Communications (2019), DOI: 10.1038/s41467-019-11921-3.
Scientific Image: Download via https://bit.ly/2mpl1sF
Photo of Organic 2D-Materials Group at the Chair for Molecular Functional Materials, Center for Advancing Electronics Dresden, TU Dresden:
Download via https://bit.ly/2ml04iG
Guest lecture - Dr. Jos Lenders, Deputy Editor of Advanced Materials, Advanced Functional Materials, and Advanced Optical Materials
September 19, 2019
Speaker: Dr. Jos Lenders, Deputy Editor of Advanced Materials, Advanced Functional Materials, and Advanced Optical Materials
Date/Time: Thursday, September 19, 2019, 3:00 pm - 4:30 pm
Location: TU Dresden, Chemie-Neubau (CHE), lecture hall CHE 091, Bergstrasse 66, 01069 Dresden
Topic: Publishing advanced materials science with Wiley under the Projekt DEAL “Publish & Read” agreement – How to maximize your success!
Congratulations to Panpan Zhang who successfully defended his PhD
September 17, 2019
Panpan Zhang successfully defended his PhD on “Development of Novel Micro-Supercapacitors with High Areal Energy Density and Smart Functions” on September 10, 2019. Congratulations Dr. Zhang!
Renhao Dong receives an ERC Starting Grant of 1.5 million EUR to develop functional conjugated 2D MOFs
Published on September 13, 2019
The European Research Council (ERC) has approved the research project "Development of Functional Conjugated Two-Dimensional Metal-Organic Frameworks (FC2DMOF)" with a prestigious and highly competitive Starting Grant of 1.5 million EUR for 5 years.
Metal-organic frameworks (MOFs) are crystalline coordination polymers that consist of metal ions connected by organic ligands, which have been highlighted for the functions in catalysis, gas storage and separation. In the past, MOFs were regarded as insulators due to the large separation of metal centers by multi-atom, insulating organic ligands, etc. Recent advances disclose that the designs of conjugated 2D MOFs (C2DMOFs) have led to improved intrinsic conductivity (up to 2500 S/cm). However, the related research remains immature due to lack of high-quality film samples, very limited structural types and elusive transport mechanism.
Dr. Renhao Dong’s ERC Starting Grant project aims to develop magnetic (semi-)conductive C2DMOFs and accomplish electronic/magnetic structure engineering for functions in electronics and spintronics. Dr. Dong and his team will design novel π-conjugated ligands to tune geometries and pore sizes of C2DMOFs, thus achieving in-plane engineering on charge and spin distribution; meanwhile, they will dedicate the development of versatile synthetic strategies towards the synthesis of highly crystalline (or single-crystalline) single-layer or few-layer C2DMOFs. By employing the developed C2DMOFs, they will explore magnetism and temperature-/magnetic/electric field-depended charge transport properties. As the key achievements, it is expected to establish novel electronic/magnetic structures and general synthesis strategies, delineation of reliable structure-transport relationships and superior device performance of C2DMOFs. This is an emerging joint research front that holds great potential for influencing the research and development in Chemistry, Materials Science and Physics.
Since Jan. 2017, Dr. Renhao Dong has been a research group leader of organic 2D materials in the Chair of Molecular Functional Materials, TU Dresden. His current scientific interests include (1) Organic synthesis of novel pi-conjugated molecules; (2) Chemistry of 2D covalent polymers: structures and synthetic methodologies (solvothermal/interfacial/CVD methods as well as liquid-phase exfoliation); (3) Functional conjugated 2D MOFs: synthesis and functions for opto-electronics, magnetics, electrocatalysis, energy storage and sensing; (4) Organic-2D-crystal-based van der Waals heterostructures.
Website of Dr. Renhao Dong: https://tu-dresden.de/mn/chemie/mc/mc2/die-professur/gruppenleiter/dr-renhao-dong
News for ERC Starting Grant 2019: https://erc.europa.eu/news/StG-recipients-2019
Chem2Dmat European conference on chemistry of two-dimensional materials was held in Dresden
September 9, 2019
The international Chem2Dmat conference was held on September 03 - 06, 2019 at the Dresden University of Technology organized by the Phantoms Foundation with local support from the Chair of Molecular Functional Materials (Prof. Xinliang Feng).
The 2nd edition of chem2Dmat has covered all areas related to 2D materials' chemistry spanning their synthesis as well as their functionalization, using covalent and non-covalent approaches, for composites, foams and coatings, membranes, (bio-)sensing, (electro- and photo-)catalysis, energy conversion, harvesting and storage, electronics, nanomedicine, biomaterials, with sessions on the following themes:
- Synthesis, processing and multiscale characterization
- Bottom-up growth
- Covalent and non-covalent functionalization
- Synthetic two-dimensional materials
- Design of 3D functional materials from layered systems
More than 90 inspiring presentations from international experts, such as Prof. Will Dichtel and Prof. Klaus Müllen showed the potential and perspectives of the future research in this area making this conference a central meeting point for the 2D material´s researcher. Furthermore, the poster session with more than 60 posters also offered young scientists the possibility to present their research on 2D materials.
Guest lecture - Prof. Yury Gogotsi, Drexel University, USA
August 29, 2019
Speaker: Prof. Yury Gogotsi, A. J. Drexel Nanomaterials Institute and Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
Date/Time: Thursday, August 29, 2019, 3:00 pm - 4:30 pm
Location: TU Dresden, Walther-Hempel-Building, Seminar room HEM 219 (second floor)
Topic: Electronic Properties of 2D Transition Metal Carbides and Nitrides (MXenes).
Dr. Jian Zhang started a Professorship in Northwestern Polytechnical University (NPU), China from March 2019
August 15, 2019
Dr. Jian Zhang has received a call for Professor in Materials Physics and Chemistry within the Department of Applied Chemistry, School of Applied and Natural Sciences, Northwestern Polytechnical University (NPU), Xi'an, P. R. China and started from March 1, 2019.
Prof. Feng elected as member of the Academy Europaea
August 13, 2019
Prof. Xinliang Feng has been elected as a member of the Academy Europaea.
The object of Academia Europaea is the advancement and propagation of excellence in scholarship in the humanities, law, the economic, social, and political sciences, mathematics, medicine, and all branches of natural and technological sciences anywhere in the world for the public benefit and for the advancement of the education of the public of all ages. The aim of the Academy is to promote European research, advise governments and international organisations in scientific matters, and further interdisciplinary and international research.
Guest lecture - Prof. Zhifeng Ren, University of Houston, USA
August 5, 2019
Speaker: Prof. Zhifeng Ren, Department of Physics and Texax Center for Superconductivity (TcSUH), University of Houston, Houston, TX 77204, USA
Date/Time: Monday, August 5, 2019, 3:00 pm - 4:30 pm
Location: TU Dresden, Walther-Hempel-Building, Seminar room HEM 219 (second floor)
Topic: Challenges and Potential Solutions to Future Energy Need.
Workshop on "Graphene and 2D materials" and 5th year anniversary celebration of the Chair for Molecular Functional Materials
August 2, 2019
On August 1, 2019 Prof. Feng celebrated the 5th year anniversary with many colleagues in a relaxed atmosphere while enjoying a delicious BBQ. Prof. Feng began his work as a cfaed strategic professor 5 years ago and has since then built up his chair with more than 60 people.
On this occassion Prof. Feng organized a 1-day workshop on "Graphene and 2D materials" inviting many colleagues and collaboration partners.
Dr. Junzhi Liu will start Professorship in Hong Kong from September 2019
July 31, 2019
Dr. Junzhi Liu has received a call for Assistant Professor in Materials Chemistry with tenure track in the Department of Chemistry at The University of Hong Kong (HKU) and will start from September 1, 2019.
Open-shell Non-benzenoid Nanographenes Containing Two Pairs of Pentagonal and Heptagonal Rings
Published on July 24, 2019
Extended polycyclic aromatic hydrocarbons, or nanographenes, which can be regarded as finite graphene segments composed of sp2-conjugated carbon atoms, have attracted tremendous interest in the last two decades due to their intriguing electronic and optoelectronic properties, leading to potential applications in organic electronics. However, most reported nanographenes consist solely of benzenoid rings. Non-benzenoid odd-membered polycycles such as pentagons and heptagons occur in graphene as localized defects and extended grain boundaries, and may significantly influence the physicochemical properties of corresponding nanostructures, arising from local changes in strain and conjugation. The known methods of graphene fabrication, however, fail to offer a rational control over the formation of non-benzenoid topologies. This limitation thus motivates their atomically-precise synthesis and comprehensive characterizations.
The group of scientists from the Chair of Molecular Functional Materials of Prof. Xinliang Feng, Prof. Klaus Müllen (MPIP) and Prof. Roman Fasel (EMPA, Zurich, Switzerland) have demonstrated a combined bottom-up in-solution and on-surface synthetic approach, reported the synthesis of non-benzenoid open-shell nanographenes containing two pairs of embedded pentagonal and heptagonal rings. The 5-7 rings embedded nanographene displays an extremely narrow energy gap of 0.27 eV and exhibits a pronounced open-shell biradical character close to 1 (y0=0.92), in which the spin densities are localized on the edges of heptagonal rings. The experimental results are supported by mean-field and multi-configurational quantum chemical calculations. Access to large nanographenes with a combination of non-benzenoid topologies and open-shell character should have wide implications in harnessing new functionalities toward the realization of future organic electronic and spintronic devices.
This work was financially supported by European Union’s Horizon 2020 research and innovation program under grant agreement No 696656 (Graphene Flagship Core2), the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden (cfaed)” and EnhanceNano (No. 391979941), the European Social Fund and the Federal State of Saxony (ESF-Project “GRAPHD”, TU Dresden), the Swiss National Science Foundation and the NCCR MARVEL funded by the Swiss National Science Foundation.
Junzhi Liu, Shantanu Mishra, Carlo A. Pignedoli, Daniele Passerone, José I. Urgel, Alberto Fabrizio, Thorsten G. Lohr, Ji Ma, Hartmut Komber, Martin Baumgarten, Clémence Corminboeuf, Reinhard Berger, Pascal Ruffieux, Klaus Müllen*, Roman Fasel*, Xinliang Feng*. J. Am. Chem. Soc, 2019, DOI: 10.1021/jacs.9b04718..
A Semiconducting Layered Metal-Organic Framework Magnet
Published on July 22, 2019
Semiconductors that display spontaneous magnetization are attractive for spintronic applications. Historically, the research of ferromagnetic semiconductor materials has been primarily focused on inorganic dilute magnetic semiconductors (DMSs) and layered inorganic two-dimensional (2D) materials. As major drawbacks, their low magnetic ordering temperature as well as poor chemical tunability greatly hindered their practical application. As a new kind of promising alternatives, metal-organic frameworks (MOFs) have been reported to show promise in tailoring the magnetic ordering temperature and carrier motilities respectively through rational design and synthesis of MOFs materials. However, the simultaneous realization of room-temperature magnetic ordering and semiconducting behavior in a MOF has not been experimentally demonstrated to date.
To address this situation, a group of scientists from the Center for Advancing Electronics Dresden (cfaed) & Department of Chemistry and Food Chemistry at TU Dresden, together with researchers from HZDR/MPIP/IKTS/IMDEA/SJTU/Leipzig have developed a semiconducting layered metal-organic framework (MOF, K3Fe2[PcFe-O8]) with spontaneous magnetization. This layered MOF features in-plane full π-d conjugation and exhibits semiconducting behavior with a room temperature carrier mobility of ~15 cm2/Vs as determined by time-resolved Terahertz spectroscopy. Magnetization experiments and 57Fe Mössbauer spectroscopy demonstrate the presence of long-range magnetic correlations in obtained K3Fe2[PcFe-O8] arising from the magnetic coupling between iron centers via delocalized π electrons. The sample exhibits superparamagnetic features due to a distribution of crystal size and possesses magnetic hysteresis up to 350 K. This work sets the stage for the development of spintronic materials exploiting magnetic MOF semiconductors.
Figure (a) Schematic illustration for the synthesis of K3Fe2[PcFe-O8] framework with iron ions and organic PcFe-OH8 linkers connected by coordination bonds (light cyan: C; blue: N; light pink: O; orange: Fe3+ in the phthalocyanine ring; green: Fe2+ in the linkage; H atoms and K+ counter-ions omitted for clarity). (b) Real (black dots) and imaginary (red dots) components of the frequency-resolved complex conductivity; solid lines represent a Drude-Smith description of the data. (c) Magnetic hysteresis loops obtained at different temperatures.
This work was financially supported by ERC Grant on 2DMATER, EU Graphene Flagship, Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET) as well as the German Science Council, Center of Advancing Electronics Dresden, EXC1056, (cfaed) and OR 349/1 and the Max Planck Society. E.C. acknowledges financial support from the Max Planck Graduate Center and the regional government of Comunidad de Madrid under project (2017-T1/AMB-5207). We also acknowledge Dresden Center for Nanoanalysis (DCN) at TUD, Dr. Petr Formanek and Dr. Konrad Schneider (Leibniz Institute for Polymer Research, IPF, Dresden), Shanghai Synchrotron Radiation Facility (SSRF, China) for the use of facilities. We appreciate Prof. Bernd Büchner, Dr. Vladislav Kataev, Dr. Yulia Krupskaya (IFW Dresden) for the helpful discussion. Prof. T. Heine and Dr. P. Petkov aknowledge the Centre for Information Services and HighPerformance Computing (ZIH) in Dresden, Germany for the provided computational resources.
Chongqing Yang, Renhao Dong*, Mao Wang, Petko St. Petkov, Zhitao Zhang, Mingchao Wang, Peng Han, Marco Ballabio, Sascha A. Bräuninger, Zhongquan Liao, Jichao Zhang, Friedrich Schwotzer, Ehrenfried Zschech, Hans-Henning Klauss, Enrique Cánovas, Stefan Kaskel, Mischa Bonn, Shengqiang Zhou, Thomas Heine, Xinliang Feng*. Nature Communications 2019, DOI: 10.1038/s41467-019-11267.
Layered Two-Dimensional Conjugated Metal-Organic Framework as Highly Efficient Electrocatalyst for Oxygen Reduction Reaction
Published on July 11, 2019
Metal-organic frameworks (MOFs), have been rising as a fascinating family of electrocatalysts with both homogeneous and heterogeneous advantages: the well-defined structures and readily accessible active sites can be tuned at the molecular level to improve the catalytic performance and also enable the MOFs to serve as model systems for fundamental understanding of catalytic mechanism. However, great challenges still plagued on the conventional MOFs including electrical insulators and blockage of metal centers by organic ligands, resulting in their inferior activity (half-wave potential E1/2 <0.8 V vs RHE) and dramatically limit their broader applications in electrocatalysis. Pyrolysis of MOFs into metal- and heteroatom-doped porous carbons has been widely demonstrated to improve the catalytic activity. However, this method has to sacrifice the well-defined molecular active sites.
In order to address these challenges, researchers from Technical University of Dresden (Chair for Molecular Functional Materials) and collaborators have developed a copper-phthalocyanine-based 2D conjugated MOF with square planar cobalt-bis(dihydroxy) complexes (Co-O4) as linkages (PcCu-O8-Co), which is atomically ordered, planar metal-organic networks along 2D directions with fully in-plane π-delocalization and weak out-plane π-π stacking. This 2D MOFs shows unique 2D features as well as improved electron transfer capacity and high utilization of exposed active sites apart from the inherited advantages of traditional MOFs. PcCu-O8-Co 2D MOF mixed with carbon nanotubes exhibits excellent electrocatalytic ORR activity (E1/2=0.83 V vs. RHE, n=3.93, and jL=5.3 mA cm-2) in alkaline media, which is the record value among the reported intrinsic MOF electrocatalysts. Supported by in-situ Raman spectro-electrochemistry and theoretical modelling as well as contrast catalytic tests, we identified the cobalt nodes as ORR active sites. Furthermore, when employed as cathode electrocatalyst for zinc-air battery, PcCu-O8-Co delivers a maximum power density of 94 mW cm-2, outperforming the state-of-the-art Pt/C (78.3 mW cm-2).
Haixia Zhong, Khoa Hoang Ly, Mingchao Wang, Yulia Krupskaya, Xiaocang Han, Jichao Zhang, Jian Zhang, Vladislav Kataev, Bernd Büchner, Inez M. Weidinger, Stefan Kaskel, Pan Liu, Mingwei Chen, Renhao Dong* & Xinliang Feng*, A Phthalocyanine‐Based Layered Two‐Dimensional Conjugated Metal–Organic Framework as a Highly Efficient Electrocatalyst for the Oxygen Reduction Reaction. Angew. Chem. Int. Ed. 2019, doi.org/10.1002/ange.201907002..
This work is financially supported from EU Graphene Flagship, ERC T2DCP, Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET), as well as the German Science Council and Center of Advancing Electronics Dresden (cfaed). H.X.Z. gratefully acknowledges funding from China Scholarship Council and Deutscher Akademischer Austauschdienst German Academic Exchange Service, the Alexander von Humboldt Foundation. I.M.W. acknowledges the Cluster of Excellence UniSysCat. We acknowledge Dresden Center for Nanoanalysis (DCN) at TUD, Dr. Petr Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) for the use of facilities. We also like to appreciate the helpful discussion from Dr. Zhongquan Liao, Mr. Zhiyong Wang and Dr. Chongqing Yang. We thank the beamline BL14W1 and BL15U1 of the Shanghai Synchrotron Radiation Facility for the XAFS measurements.
Synthesis and characterisation of π-extended Triangulene
Published on July 3, 2019
Researchers from the Chair of Molecular Functional Materials of Prof. Xinliang Feng and the research group of Prof. Roman Fasel (EMPA, Zurich, Switzerland) recently reported the synthesis and characterization of the elusive π-extended triangulene – a non-Kekulé high-spin nanographene potentially useful in carbon-based spintronic. The π-extended triangulene with the structural formula C33H15 was obtained via combined in-solution and on-surface synthesis approach. Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) were employed to characterize the π-extended triangulene at the sub-molecular level. In particular, STS data confirm the expected presence of three unpaired electrons that couple to form a high-spin quartet ground state when the π-extended triangulene is adsorbed on a gold surface.
“Synthesis and Characterization of π-Extended Triangulene”. Shantanu Mishra, Doreen Beyer, Kristjan Eimre, Junzhi Liu, Reinhard Berger, Oliver Gröning, Carlo A. Pignedoli, Klaus Müllen, Roman Fasel, Xinliang Feng, Pascal Ruffiuex. J. Am. Chem. Soc. 2019, xxx. DOI: 10.1021/jacs.9b05319.
This work was financially supported by the Swiss National Science Foundation (grant numbers 200020-182015 and IZLCZ2-170184), the NCCR MARVEL funded by the Swiss National Science Foundation (grant number 51NF40-182892), the European Union’s Horizon 2020 research and innovation program under grant agreement numbers 696656 and 785219 (Graphene Flagship Core 2), the Office of Naval Research (grant number N00014-18-1-2708), ERC Consolidator grant (T2DCP, number 819698), the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden (cfaed)” and EnhanceNano (number 391979941), and the European Social Fund and the Federal State of Saxony (ESFProject “GRAPHD”, TU Dresden). Computational support from the Swiss Supercomputing Center (CSCS) under project ID s904 is gratefully acknowledged.
Mechanically strong MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators
Published on July 2, 2019
Two-dimensional nanofluidic channels are emerging candidates for capturing osmotic energy from salinity gradients. However, present two-dimensional nanofluidic architectures are generally constructed by simple stacking of pristine nanosheets with insufficient charge densities and exhibit low-efficiency transport dynamics, consequently resulting in undesirable power densities of less than 1 W m-2.
The researchers from Technische Universität Dresden (Chair for Molecular Functional Materials) demonstrate a high-performance nanofluidic osmotic power generator by hybridizing 2D MXene nanosheets with 1D Kevlar nanofibers (ANFs). The ANF can serve as an intercalating agent that will enlarge the interlayer channel and prevent the restacking of adjacent MXene nanosheets. More importantly, the ANFs are negatively charged in solution and their entanglement in confined channel can create a negatively charged space charge zone. By mixing artificial river water and sea water, the output power density can achieve ~3.7 W m-2, which is the highest value ever reported in both 1D and 2D nanofluidic channel membrane systems. Replacing the artificial water with natural water resource can contribute to a substantially high power density about 4.1 W m-2, much closer to the commercialization benchmark. Additionally, benefitting from the introduction of ultrastrong structural unit ANF, the composite membrane also exhibits excellent mechanical strength and good stability, showing great application prospects. This work highlights the promise in the coupling of surface charge and space charge in nanoconfinement for energy conversion driven by chemical potential gradients.
This work was supported by the Alexander von Humboldt Foundation, the European Union’s Horizon 2020 research and innovation program under grant agreement No. 785219, the European Science Foundation (ESF), and the Coordination Networks: Building Blocks for Functional Systems (SPP1928, COORNET). The authors acknowledge the Dresden Center for Nanoanalysis (DCN) at TU Dresden.
Zhen Zhang, Sheng Yang, Panpan Zhang, Jian Zhang, Guangbo Chen, and Xinliang Feng*, Mechanically strong MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators. Nat. Commun. 2019, DOI: 10.1038/s41467-019-10885-8.
Radio report on Graphene - Interview with Prof. Xinliang Feng
June 27, 2019
Radio interview by Frank Grotelüschen with Prof. Xinliang Feng on the topic of Graphene and demineralisation/water processing published on radio channel "Deutschlandfunk".
Guest lecture - Prof. Tien-Yau Luh, National Taiwan University
Published on June 26, 2019
Speaker: Prof. Tien-Yau Luh, Department of Chemistry, National Taiwan University, Taipei, Taiwan
Date/Time: Monday, July 8, 2019, 3:00 pm - 4:00 pm
Location: TU Dresden, Walther-Hempel-Building, Seminar room HEM 219 (second floor)
Topic: From One-dimensional Ladderphanes to Two-dimensional Stromaphanes.
Guest lecture - Prof. Shie-Ming Peng, National Taiwan University
Published on June 26, 2019
Speaker: Prof. Shie-Ming Peng, Department of Chemistry, National Taiwan University, Taipei Taiwan, Institute of Chemistry, Academia Sinica, Taipei Taiwan
Date/Time: Monday, July 8, 2019, 2:00 pm - 3:00 pm
Location: TU Dresden, Walther-Hempel-Building, Seminar room HEM 219 (second floor)
Topic: Molecular Metal Wires from Homonuclear Metal String Complexes to Heteronuclear Metal String Complexes.
Guest lecture - Prof. Michael Mastalerz, Ruprecht-Karls-Universität Heidelberg
Published on June 7, 2019
Speaker: Prof. Michael Mastalerz, Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg
Date/Time: Thursday, June 13, 2019, 15:00 - 16:30
Location: TU Dresden, Chemie-Neubau, CHE 183 (first floor)
Topic: From Soluble Porous Cages to Extended fused π-Systems.
CSC-Award granted to Faxing Wang and Panpan Zhang
June 7, 2019
Faxing Wang and Panpan Zhang, two PhD students in Prof. Feng's chair at TU Dresden, have recently been granted "the 2018 Chinese Government Award for Outstanding Self-financed Students Abroad" by the China Scholarship Council. This award was founded by the Chinese government in 2003 and aims at rewarding the academic excellence of self-financed Chinese students studying overseas. Only those with outstanding performance in their PhD studies will be considered by the award panel and no more than 500 young talents will be granted the award each year all over the world.
Guest lecture - Dr. Jeremy Allen, Royal Society of Chemistry
Published on June 7, 2019
Speaker: Dr. Jeremy Allen, Deputy Editor, Chemical Science, Royal Society of Chemistry
Date/Time: Monday, May 20, 2019, 10:00 - 11:00 AM
Location: TU Dresden, Chemie-Neubau, CHE 182 (first floor)
Topic: My role within a societal publisher and tips on how to publish your scientific research.
Atomically Dispersed Nickel–Nitrogen–Sulfur Species Anchored on Porous Carbon Nanosheets for Water Oxidation
Published on April 9, 2019
Exploring earth-abundant, active and stable electrocatalysts to replace noble metal catalysts for oxygen evolution reaction (OER) through alkaline water photoelectrolysis and electrolysis system is a key to develop sustainable energy conversion technologies. Despite certain progress made in the development of heteroatom-doped carbon materials in the past, especially the transitional metal-N (TM–Nx) doped nanocarbons catalysts, the application of TM–Nx-doped nanocarbons in OER electrocatalysis is in infancy, and the overall catalytic performance of TM–Nx-doped nanocarbons is far from satisfactory for practical applications.
Here, Prof. Dr. Xinliang Feng (Technische Universität Dresden, Germany), Prof. Dr. Yang Hou (Zhejiang University, China), and colleagues report a 2D nanocarbon hybrid electrocatalyst comprised of atomically dispersed Ni atoms coordinated with three nitrogen and one sulfur atoms in porous carbon nanosheets (S|NiNx-PC). Benefiting from the abundant porous architecture and well-distributed active sites, the achieved S|NiNx-PC/EG nanosheets electrode displays outstanding electrocatalytic activity and durability for OER with a low overpotential of 1.51 V at 10 mA cm-2 and a small Tafel slope of 45 mV dec-1 in alkaline media. The overpotential for the S|NiNx-PC/EG is the lowest among all heteroatom- and/or transition metal-doped carbon electrocatalysts for OER reported thus far, and it even surpasses the state-of-the-art commercial Ir/C catalyst. Moreover, an integrated photoanode of nanocarbon on a Fe2O3 nanosheet array enables highly active solar-driven oxygen production.
Experimental results reveal that the well-dispersed molecular S|NiNx species act as active sites for catalyzing OER, where the incorporated S atoms can effectively tune the hybridization state of the Ni and N atoms and enhance the electron transfer, thus synergistically promoting the oxidation kinetics. Theoretical calculations manifest that the coordination of Ni–Nx centers hybridized with that of neighboring S atom creates sufficient localized reactive sites by modifying the local charge distribution on the carbon surface and reducing the potential barriers of the elementary reactions, thereby boosting its OER kinetics. More importantly, the accurate atomic structure of isolated Ni atoms coordinated with three N atoms and one S atom in the carbon matrix for the S|NiNx active centers is clearly disclosed by aberration-corrected scanning transmission electron microscopy, atomic electron energy loss spectroscopy and synchrotron radiation X-ray absorption spectroscopy together with DFT-simulated scanning tunneling microscopy. This work was published at Nat. Commun. 2019, doi: 10.1038/s41467-019-09394-5.
Dr. Lucia Gemma Delogu received call for Professorship in Padua
April 4, 2019
Dr. Lucia Gemma Delogu has received a call for professor in Biochemistry with tenure track at the Department of Biomedical Sciences at the University of Padua Italy.
ERC Consolidator Grant für Prof. Xinliang Feng
March 7, 2019
Im Februar 2019 wurde die Vereinbarung über einen „Consolidator Grant“ des Europäischen Forschungsrates ERC für Prof. Xinliang Feng unterschrieben. Der Projekttitel lautet „T2DCP – Development of Thiophene Based Conjugated Polymers in Two Dimensions“, der Grant läuft über fünf Jahre und ist mit einem Volumen von zwei Millionen Euro ausgestattet. Es ist geplant, fünf Postdocs und vier Doktoranden in das Projekt einzubeziehen, da es eine sehr breite Palette von Forschungsthemen abdeckt.
Der Europäische Forschungsrat hat das Consolidator-Programm aufgelegt, um Wissenschaftlern auf einer fortgeschrittenen Karrierestufe eine größere Unabhängigkeit durch den (weiteren) Aufbau ihres Forschungsteams und die Weiterentwicklung einer erfolgreichen Karriere in Europa zu ermöglichen. Der ERC fördert damit Projekte, bei denen ein einzelner Forscher als Principal Investigator auftritt und die an einer beliebigen Gastinstitution in einem Mitgliedsland der EU durchgeführt werden.
Prof. Feng leitet die Strategische cfaed-Professur für Molekulare Funktionsmaterialien an der TU Dresden und beschäftigt sich hauptsächlich mit 2D-Materialien, die aus nur einer einzigen Atomlage bestehen. In diesem Jahr wird er sein 5-jähriges Jubiläum am Exzellenzcluster begehen.
Dr. Wee Jun Ong, BMBF Green Talents Award Winner joins Prof. Feng's chair
February 25, 2019
Dr. Wee Jung Ong, Assistant Professor at Xiamen University Malaysia and BMBF Green Talents Award winner, has joined our chair on February 25, 2019. During his three months research stay he aims to work on the sustainable energy development and simultaneously to address the present energy and environmental-related issues, which are two of the biggest challenges in society today.
Prof. Feng elected as member of the European Academy of Sciences
Feburary 22, 2019
Prof. Xinliang Feng has been elected as a member of the European Academy of Sciences (EurASc).
The European Academy of Sciences (EURASC) is a non-profit non-governmental, independent organization which units the most distinguished scholars and engineers performing forefront research and the development of advanced technologies.
The mission of EURASC is to promote excellence in science and technology and it plays an essential role in fostering social and economic development and progress. The official name of the institution is European Academy of Sciences (Académie Européenne des Sciences).
Advanced Materials Hall of Fame laureates highlighted on Advanced Science News
January 17, 2019
Advanced Materials Hall of Fame laureates highlighted on Advanced Science News
2nd Graphene Flagship EU-China Workshop was held in Dresden
December 13, 2018
The 2nd Graphene Flagship EU-China Workshop on Graphene and related 2D materials was held on 07-08 December 2018 at Pullman Hotel in Dresden organized by Graphene Flagship and Chair of Molecular Functional Materials (Prof. Xinliang Feng).
During the workshop speakers from China and European countries presented their current works and exchanged their experiences and ideas related to the current and emerging topics associated with the fundamental materials synthesis, physics and devices for graphene and related 2D materials. At the end of the workshop, Chinese and European speakers have built new collaborations base on the presented works in the workshop.
Dr. Zhen Zhang received the prestigious Humboldt Research Fellowship for Postdoctoral Researchers
November 27, 2018
The Humboldt Research Fellowship is awarded to researchers from abroad with above average qualifications and who are at the beginning of their career. By being granted this fellowship, Dr. Zhen Zhang, will receive financial support for two years to carry out his research in the research group of Prof. Xinliang Feng at Technische Universität Dresden.
Highly Cited Researcher 2018
November 27, 2018
Prof. Dr. Xinliang Feng has been listed as highly cited researcher in 2018 for his research performance demonstrated by the production of multiple highly cited papers that rank in the top 1% by citations for field and year in Web of Science.
Fluoride-Free Synthesis of Two-Dimensional Titanium Carbide (MXene)
Published on October 18, 2018
MXenes are a fascinating class of two-dimensional (2D) materials that consist of few atoms thick layers of transition metal carbides, nitrides or carbonitrides. They have aroused increasing attention due to their unique combination of hydrophilic properties and good electrical conductivity. The production of MXene relies on chemical etching of aluminium (Al) layers from titanium aluminium carbide (Ti3AlC2, a MAX phase). Although diverse etching conditions have been identified, the state-of-the-art strategies require the handling of hydrofluoric acid or fluoride-based compounds, which result in highly toxic and corrosive liquid waste, and the functionalization of Ti3C2 surfaces with fluorine- and oxygen-containing terminations. Along with the considerable safety issues, fluoridated etchants have negative impact on the specific capacitance of etched materials when used as electrodes for supercapacitors.
To address these problems, researchers from Technical University of Dresden (Chair for Molecular Functional Materials) and collaborators have developed an efficient electrochemical strategy to prepare Ti3C2Tx (T=O, OH) (MXene) in a binary aqueous system. The anodic etching of Al atoms followed by the replacement with hydroxide groups enable the formation of single or bilayer sheets with high yield (>90 %) and large average dimension. The results are comparable or even better than those made from classic etching techniques using HF or LiF/HCl. For the use as energy storage materials, all-solid-state supercapacitors assembled with Ti3C2Tx films deliver a high areal capacitance of 220 mF cm-2 (scan rate: 10 mV s-1). More importantly, this method does not require any dangerous fluoride-containing agents or harsh etching conditions, therefore it is appealing for the practical production of novel MXene materials.
This work was financially supported by the Deutsche Forschungsgemeinschaft (MX-OSMOPED project), ERC grants on 2DMATER, Graphene Core 2 and EC under Graphene Flagship (NO. CNECT-ICT-604391) and Center for Advancing Electronics Dresden (cfaed).
Sheng Yang, Panpan Zhang, Faxing Wang, Antonio Gaetano Ricciardulli, Martin R. Lohe, Paul W. M. Blom & Xinliang Feng*, Fluoride-Free Synthesis of Two-Dimensional Titanium Carbide (MXene) Using A Binary Aqueous System. Angew. Chem. Int. Ed. 2018, DOI: 10.1002/anie.201809662
MOFtronics: 2D metal-organic frameworks are ready for electronics
Published on October 16, 2018
A group of scientists has observed for the first time band-like electron transport in a conjugated two-dimensional (2D) metal-organic framework film (Nature Materials, "High-mobility band-like charge transport in a semiconducting two-dimensional metal–organic framework"). This semiconducting behavior, together with its cost-effective production, opens the path for employing metal-organic frameworks as electroactive materials in electronic devices.
The 21st century has seen a reinvention of how modern electronics impact our daily lives. Inorganic semiconductors as silicon, germanium or gallium arsenide are at the core of modern electronics; they are currently widely employed in e.g. computer chips, LEDs and solar cells. Inorganic semiconductors are highly pure, crystalline and hence ordered materials, these features make them good conductors of electricity under the application of an external bias (e.g. by applying a voltage). As a drawback, their high crystallinity and purity is reached by high temperature processing and then, they are very expensive to produce. A low-cost alternative are organic based semiconductors as e.g. polymers, these can be processed at room temperatures.
The scientists from TU Dresden/MPI-P/IMDEA Nanociencia/HZDR/MPI-CPS/Sofia have now developed and characterized a novel metal-organic framework (MOF) material, an organic graphene-like two-dimensional (2D) material made at room temperature that, remarkably, behaves electrically as inorganic semiconductors. These results open the path for exploiting MOFs as electroactive materials in electronic devices.
Figure (a) A high-resolution transmission electron microscopy image of the conjugated 2D MOF together with the structural schematic (grey, yellow and orange: carbon, sulfur and iron atoms, respectively). (b and c) Transport studies by THz spectroscopy and Hall effect measurements, respectively.
MOFs are crystalline coordination polymers that consist of metal ions connected by organic ligands. In the past, MOFs were regarded as insulators due to the large separation of metal centers by multi-atom, insulating organic ligands, etc. The new conjugated 2D MOF, produced by the team of Dr. Renhao Dong and Prof. Xinliang Feng in TU Dresden, is a highly crystalline film, obtained from trigonal planar organic ligands that are coordinated by square-planar atomic metal nodes. Such design rendering graphene-like conjugated planar geometry induces full delocalization of p-electrons in 2D, leading to a largely improved conductivity and a narrowed band gap.
The group led by Dr. Enrique Cánovas in MPI-P/IMDEA Nanociencia characterized the 2D MOFs by Terahertz (THz) spectroscopy, a tool that measure the conductivity of a sample in ultrafast time scales (10-12 seconds), locally (measuring currents over distances as short as 10-9 meters) and optically (without the need of applying perturbative metal contacts). These aspects enabled THz spectroscopy to assess the dependence with frequency for the conductivity in the 2D MOF, which turns out to obey a “Drude” behaviour; the same found in e.g. in highly crystalline silicon. From the Drude response, resolved by THz spectroscopy in the novel 2D MOFs, a world record electron mobility was inferred, that surpass previous values, obtained in insulating MOFs, by a factor of 10000.
The “Drude” behaviour implies that electrons can be displaced very easily over very long distances when a voltage is applied. As contrast, a Hall effect measurement by the group led by Dr. Artur Erbe in HZDR based on a “real” electronic device further confirmed the high mobility in this novel MOF. These results open the path for exploiting low cost MOFs in a plethora of novel applications where long-range motion of electrons is desired (e.g. in electronic devices).
This research is a joint collaboration between scientists from Germany, Bulgaria and Spain. The Technical University of Dresden, the Max Planck Institute for Polymer Research, the Max Planck Institute for Chemical Physics of Solids, the Helmholtz Zentrum in Dresden, the Wilhem-Ostwald-Institute of Physical and Theoretical Chemistry in Leipzig, The University of Sofia and the Madrid’s Institute of Advanced Studies IMDEA Nanociencia contributed to this work.
Renhao Dong, Peng Han, Himani Arora, Marco Ballabio, Melike Karakus, Zhe Zhang, Chandra Shekhar, Peter Adler, Petko St. Petkov, Artur Erbe, Stefan C. B. Mannsfeld, Claudia Felser, Thomas Heine, Mischa Bonn, Xinliang Feng and Enrique Cánovas. High-mobility band-like charge transport in a semiconducting two-dimensional metal–organic framework. Nature Materials 2018, online.
This work was financially supported by the ERC Grant on 2DMATER, HIPER-G and EU Graphene Flagship, European Science Foundation (ESF), SPP 1928 (COORNET) and the German Science Council. Financial support by the Max Planck Society is also acknowledged. We acknowledge the CFAED (Center for Advancing Electronics Dresden). E.C. acknowledges financial support from the Max Planck Graduate Center and the Regional Government of Comunidad de Madrid under project 2017-T1/AMB-5207. R.D. gratefully appreciates funding from the Alexander von Humboldt-Foundation. H.A. and A.E. are grateful to the Initiative and Networking Fund of the Helmholtz Association of German Research Centers through the International Helmholtz Research School for Nanoelectronic Networks, IHRS NANONET (VH-KO-606). We appreciate LPKF Laser & Electronics for the fabrication of the Hall bar geometry by laser ablation. We acknowledge the Dresden Center for Nanoanalysis (DCN) at TUD and P. Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) for the use of facilities, and we appreciate X. Zhang, T. Zhang, F. Ortmann and K. S. Schellhammer for the helpful discussion. P.P. and T.H. thank ZIH Dresden for providing high-performance computing facilities.
Marcus Richter wins the RSC poster prize at EuCheMS 2018
Published on September 5, 2018
Congratulations to our PhD student Marcus Richter for the honour to win the Royal Science Chemistry (RSC) poster prize at the EuCheMS conference 2018, which was sponsored by the three RSC journals Nanoscale, Nanoscale Advances and Nanoscale Horizons.
The 7th EuChemS Congress is an internationally respected, large-scale event for chemical sciences, which was held from 26th to 30th August 2018 in Liverpool. This conference had a wide selection of current research topics in chemistry and was highlighted by expert talks from noble prize winner Ben Feringa, Michael Grätzel or Omar Yaghi.
Guest lecture - Prof. Yoshito Tobe, Osaka University
Published on August 28, 2018
Speaker: Prof. Yoshito Tobe, Osaka University
Date/Time: Friday, August 31, 2018, 02:00 PM - 03:30 PM
Location: TU Dresden, Walther-Hempel-Building, HEM 219 seminar room (second floor)
Topic: Porous Self-Assembled Monolayers at Solution/Graphite Interfaces: From On-Surface Chirality to Molecular Lithography
Symposium at TU Dresden in celebration of 30 years „Wiley‘s Advanced Materials“
Published on July 27, 2018
Exactly 30 years ago, Advanced Materials - the scientific journal focusing on innovative materials research - saw the light of day. On this occasion the TU Dresden was proud to organize a scientific symposium with the topic "Advanced Carbon & 2D Materials" in honour of this first-class journal which is pioneering in the field of chemistry and materials research. 24 world-renowned scientists from all over the world gave an insight into their groundbreaking research in these fields.
A large number of young scientists followed the inspiring lectures and had the opportunity to present their latest research results to the experts in these research fields, but also to high-ranking representatives of the journal and the publishing house Wiley-VCH, resulting in a stimulating scientific exchange.
It can be said that this symposium was a complete success due to its internationality, the diversity of research and the numerous discussions - both for "Advanced Materials" and Wiley-VCH, the participating (young) scientists and the materials research location TU Dresden.
Magnetic semiconducting 2D MOF
Published on July 10, 2018
Metal-organic frameworks (MOFs) so far have been highlighted for their potential roles in catalysis, gas storage and separation. However, the realization of high electrical conductivity (>10-3 S/cm) and magnetic ordering in MOFs will afford them new functions for spintronics, which remains relatively unexplored.
The groups from cfaed/TUD/HZDR/MPICPS/IKTS/XJTU demonstrate the synthesis of a two-dimensional MOF (2D MOF) by solvothermal methods using perthiolated coronene, namely 1,2,3,4,5,6,7,8,9,10,11,12-perthiolated coronene (PTC, reported by the same group (J. Am. Chem. Soc., 2017, 139, 2168-2171)), as a ligand and planar iron-bis(dithiolene) as linkages enabling a full p-d conjugation. Thus, such 2D MOF is featured with hexagonal lattices and van der Waals layer-stacking structure. Van der Pauw electrical measurement reveals the room temperature conductivity value of ~10 S/cm for bulk compressed pallet. A variable-temperature conductivity measurement displays a non-linear increase of conductivity with temperature, indicating a typical semiconducting behavior. A density functional theory (DFT) calculation is carried out to estimate the band gap as ~0.2 eV for a monolayer MOF. A variable-temperature magnetic susceptibility measurement as well as 57Fe Mössbauer spectra demonstrated that the PTC-Fe exhibit ferromagnetic ordering within nanoscale magnetic clusters at low temperatures (below ~20 K), thus evidencing exchange interactions between the intermediate spin iron(III) centers via the delocalized p electrons. Our work highlights conjugated 2D MOFs as a class of conductive materials exhibiting ferromagnetic and semiconducting features for potential spintronics application.
This work was financially supported by the ERC Grant on 2DMATER, EU Graphene Flagship, SPP 1928 (COORNET) and the German Science Council. We acknowledge the cfaed (Center for Advancing Electronics Dresden). We also thank Beamline BL14W1 at the Shanghai Synchrotron Radiation Facility (SSRF) for providing the beamtimes to carry out the XAS measurements. We acknowledge Dresden Center for Nanoanalysis (DCN) at TUD and Dr. Petr Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) for the use of facilities, and we like to appreciate Prof. Stuart Parkin, Dr. Binghai Yan, Dr. Reinhard Berger and Mr. Chi Xu for the helpful discussion.
Renhao Dong, Zhitao Zhang, Diana C. Tranca, Shengqiang Zhou, Mingchao Wang, Peter Adler, Zhongquan Liao, Feng Liu, Yan Sun, Wujun Shi, Zhe Zhang, Ehrenfried Zschech, Stefan C.B. Mannsfeld, Claudia Felser & Xinliang Feng*, A coronene-based semiconducting two-dimensional metal-organic framework with ferromagnetic behavior. Nat. Commun. 2018, DOI: 10.1038/s41467-018-05141-4.
Graphene 2018 Conference was successfully held in Dresden
Published on July 5, 2018
The 8th edition of International Graphene Conference series, the largest European Event in Graphene and 2D Materials with nearly 650 participants from different scientific institutes and industries was successfully held in Dresden from the 26th to 29th of June 2018. The conference covered all areas related to Graphene and 2D Materials including chemistry, physics, material science and engineering. Moreover, within Exhibition and 2 days INDUSTRIAL FORUM, most recent technologies and business opportunities in Graphene and 2D Materials commercialization were presented.
EU Graphene Flagship Meeting took place in Dresden on June 25th 2018
Published on June 26, 2018
On June 25th a meeting of the EU Graphene Flagship with 27 participants from different European institutes and companies took place at TU Dresden. The chair for molecular functional materials (Prof. Xinliang Feng) is the leader of working package 13 (Functional Foams and Coatings) of this EU Flagship project and the purpose of this meeting was to discuss initial results and future perspectives in the field of graphene and related 2D material. The special focus of this meeting was the use of graphene and 2D materials in coatings and porous structures like foams and membranes for applications such as energy storage and conversion, catalysis, water filtration and environmental protection.
EU-40 materials prize awarded to Prof. Xinliang Feng at the e-MRS 2018 Spring Meeting in Strasbourg
Published on June 21, 2018
Prof. Xinliang Feng, cfaed Chair for Molecular Functional Materials, has been announced as the winner of the 2018 edition of the EU-40 Materials Prize for his outstanding and innovative contributions to Materials Research in Europe.
The EU-40 Materials Prize is awarded to researchers under 40 who have a major impact in the field and show exceptional promise for leadership. This prestigious award consists of a 5,000 Euro cash prize, a certificate, waiver of the meeting registration fee and a plenary talk at the Spring Meeting of the European Materials Research Society where the award was presented. The award ceremony took place on June 20, 2018 in Strasbourg, France.
Toward Full Zigzag-Edged Nanographenes: peri-Tetracene and Its Corresponding Circumanthracene
Published on May 8, 2018
Story of peri-acene (n-PA) molecules started one century ago. Apart from perylene (R. Scholl, 1910) and bisanthene (E. Clar, 1948), all n-PAs are theoretically predicted to show singlet biradical ground state (open-shell), and, hence unstable under ambient conditions. After several decades of waiting, recently, researchers from Technische Universität Dresden (Chair for Molecular Functional Materials, cfaed) and collaborators tackle the synthetic challenges to realize peri-tetracene (4-PA), the next higher analogue, in solution via steric-protection of its active zigzag edges.
This work has been published in Journal of the American Chemical Society (J. Am. Chem. Soc., 2018, DOI: 10.1021/jacs.8b03711). The authors demonstrated the synthesis and characterization of the hitherto unknown 4-PA by a rational bottom-up strategy. The phenyl substituents at the zigzag periphery of 4-PA not only offer stability, but also enhance its solubility in common organic solvents. The obtained 4-PA possesses a singlet biradical character (y0 = 72%) and exhibits remarkable persistent stability with a half-life time (t1/2) of ∼3 h under ambient conditions. UV–vis–NIR and electrochemical measurements reveal a narrow optical/electrochemical energy gap (1.11 eV) for 4-PA. Moreover, the bay regions of 4-PA enable the efficient 2-fold Diels–Alder reaction, yielding a novel full zigzag-edged circumanthracene (CA).
This work was financially supported by ERC grants on 2DMATER, the European Union’s Horizon 2020 research and innovation programme under grant agreement No 696656 (Graphene Flagship Core1), Center for Advancing Electronics Dresden (cfaed), European Social Fund and the Federal State of Saxony (ESF-Project “GRAPHD”, TU Dresden). J.J.W. thanks the DFG for funding a Rigaku Oxford Diffraction SuperNova system with a dual source (INST 269/618-1). The authors acknowledge the use of computational facilities at the Center for information services and high performance computing at TU Dresden.
M. R. Ajayakumar, Y. Fu, J. Ma, F. Hennersdorf, H. Komber, J. J. Weigand, A. Alfonsov, A. A. Popov, R. Berger, J. Liu, K. Müllen, X. Feng, J. Am. Chem. Soc., 2018, DOI: 10.1021/jacs.8b03711).
New understanding on graphite: a high power cathode material
Published on April 24, 2018
As conventional Li-ion batteries are approaching the bottleneck of energy and power limit, new energy storage technologies with fast-charging feature but based on low-cost materials are highly desirable for future sustainable and scalable applications. To construct next-generation quick-charge batteries, the key lies at developing high power cathodes. However, conventional strategies heavily relied on nanoengineering approaches sacrificing the scalability and battery cost.
The group from cfaed/ Technische Universität Dresden provides another option to build high power cathodes, where inexpensive graphite powders were exploited as the active cathode material. The disintegration problem of graphite cathode, that suffers from large volume change (>130%) during anion (de)intercalation, was well suppressed by utilizing a strong aqueous binder, alginate sodium. Then the mechanically stable electrode functioned as a reliable platform to investigate the electrochemical performance of graphite cathode and reaction kinetics of anion intercalation process. Ultrahigh power density of 42.9 kW/kg at the energy density of 334 Wh/kg and long cycling life (>10000 cycles) were achieved on commercial bulk graphite, surpassing conventional cathodes for Li-ion batteries. The kinetics analysis further revealed that, for the first time, anion intercalation into graphite is a self-activating and fast (pseudo)capacitive process. The kinetical differences between anion intercalation and cation intercalation into graphitic carbon materials were also identified in the paper.
Title: Self-activating, capacitive anion intercalation enables high-power graphite cathodes. Adv. Mater., 2018, 1800533.
Copper-surface-mediated synthesis of acetylenic carbon-rich nanofibers for active metal-free photocathodes
Published on March 23, 2018
Researches from the Chair for Molecular Functional Materials of Prof. Xinliang Feng, and other research groups in Germany, China and Italy have recently published a paper in Nature Communications on 19th March 2018, titled “Copper-surface-mediated synthesis of acetylenic carbon-rich nanofibers for active metal-free photocathodes”. This work reported a facile and scalable approach for the synthesis of acetylenic carbon-rich nanofibers (i.e. polytriethynylbenzene, PTEB) via Cu-surface mediated Glaser polycondensation. The as-prepared PTEB nanofibers on conductive substrates can be directly utilized as metal-free photocathodes in photoelectrochemical cells (PECs) for hydrogen production, and the photocurrent can be increased through the introduction of thienothiophene segment into the PTEB nanofibers. This work highlights the promise of utilizing acetylenic carbon-rich materials as efficient and sustainable photocathodes for hydrogen production.
“Copper-surface-mediated synthesis of acetylenic carbon-rich nanofibers for active metal-free photocathodes”. Tao Zhang, Yang Hou, Volodymyr Dzhagan, Zhongquan Liao, Guoliang Chai, Markus Löffler, Davide Olianas, Alberto Milani, Shunqi Xu, Matteo Tommasini, Dietrich R.T. Zahn, Zhikun Zheng, Ehrenfried Zschech, Rainer Jordan & Xinliang Feng. Nat. Commun., 2018, 9, 1140. Doi: 10.1038/s41467-018-03444-0
This work was financially supported by the ERC Grant 2DMATER, ESF Young Researcher Group ‘GRAPHD,’ and the EC under the Graphene Flagship (number CNECTICT-604391). The German Excellence Initiative via the Cluster of Excellence EXC1056 “Center for Advancing Electronics Dresden” (cfaed) is gratefully acknowledged.
A Delamination Strategy for Thinly Layered Defect-Free High-Mobility Black Phosphorus Flakes
Published on March 23, 2018
Extraordinary electronic and photonic features render black phosphorus (BP) an important material for the development of novel electronics and optoelectronics. Despite recent progress in the preparation of thinly layered BP flakes, scalable synthesis of large-size, defect-free BP flakes remains a major challenge. An electrochemical delamination strategy is demonstrated that involves intercalation of diverse cations in non-aqueous electrolytes, thereby peeling off bulk BP crystals into defect-free flakes comprising only a few layers. The interplay between tetra-n-butylammonium cations and bisulfate anions promotes a high exfoliation yield up to 78 % and large BP flakes up to 20.6 µm. Bottom-gate and bottom-contact field-effect transistors, comprising single BP flakes only a few layers thick, exhibit a high hole mobility of 252±18 cm2V-1s-1 and a remarkable on/off ratio of (1.2±0.15)×105 at 143 K under vacuum, comparable with the electronic properties of mechanically exfoliated BP flakes. This efficient and scalable delamination method opens new opportunities for the development of BP-based composites and optoelectronic devices. The related work has published in Angew. Chem. Int. Ed.
Sheng Yang, Ke Zhang, Antonio Gaetano Ricciardulli, Panpan Zhang, Zhongquan Liao, Martin R. Lohe, Ehrenfried Zschech, Paul W. M. Blom, Wojciech Pisula, Klaus Müllen* and Xinliang Feng*, Angew. Chem. Int. Ed, 2018, DOI: 10.1002/anie.201801265
This work is financially supported by ERC grants on 2DMATER, Graphene Core 1 and EC under Graphene Flagship (NO. CNECT-ICT-604391) and Center for Advancing Electronics Dresden (cfaed).
Graphene 2018 will take place in Dresden
Published January 12, 2018
Prof. Xinliang Feng is one of the co-organizers of the Graphene 2018 conference which will take place in Dresden (Germany) from June 26 – June 29, 2018. The 8th edition of Graphene Conference series is the largest European Event in Graphene and 2D Materials.
Exploration of pyrazine-embedded antiaromatic polycyclic hydrocarbons generated by solution and on-surface azomethine ylide homocoupling
Published on December 12, 2017
Researches from the Chair for Molecular Functional Materials of Prof. Xinliang Feng at Dresden University of Technology, Max-Planck Institute for Polymer Research Mainz, Technical University of Munich and Linköping University, recently, explored an unprecedented way of doping Graphene by incorporating antiaromatic units in the basal plane.
In the joint publication “Exploration of pyrazine-embedded antiaromatic polycyclic hydrocarbons generated by solution and on-surface azomethine ylide homocoupling” in Nature Communications, Xiao-Ye Wang, Marcus Richter, Yuanqin He, Jonas Björk, Alexander Riss et al. (all authors contributed equally) demonstrated azomethine ylide homocoupling as a strategy to synthesize non-planar polycyclic aromatic hydrocarbons in solution and planar nanographenes on surfaces, embeding a central pyrazine ring. The antiaromaticity of the central pyrazine ring is indicated by optical absorption spectroscopy in conjunction with theoretical calculations. This strategy opens up methods for chemically tailoring graphene and nanographenes, modified by antiaromatic dopants.
“Exploration of pyrazine-embedded antiaromatic polycyclic hydrocarbons generated by solution and on-surface azomethine ylide homocoupling”. Xiao-Ye Wang, Marcus Richter, Yuanqin He, Jonas Björk, Alexander Riss, Raju Rajesh, Manuela Garnica, Felix Hennersdorf, Jan J. Weigand, Akimitsu Narita, Reinhard Berger, Xinliang Feng, Willi Auwärter, Johannes V. Barth, Carlos-Andres Palma, Klaus Müllen, Nat. Commun., 2017, 8, 1948.
C.-A.P. was supported from the European Union’s Horizon 2020 research and innovation program 2D ink (no. 664878). X.-Y.W. is grateful to a fellowship from the Alexander von Humboldt Foundation. R.B. appreciates
support by European Social Fund and the Federal State of Saxony (ESF-Project “GRAPHD”). M.G. acknowledges the H2020-MSCA-IF-2014 program and W.A. a Heisenberg professorship by the DFG. This work was partially
supported by the ERC Consolidator Grant NanoSurfs (no. 615233), the Max Planck Society, the German Excellence Initiative“Center for Advancing Electronics Dresden” (cfaed), and the Graphene Flagship.
14th European Conference on Molecular Electronics (ECME) was successfully held in Dresden
Published October 6, 2017
Prof. Xinliang Feng was one of the co-organizers of the successful ECME conference which was held from August 29 – September 2 2017. The workshop took place in Dresden and covered all areas related to molecular -organic and plastic- electronics including chemistry, physics, biology, materials science, nanoscience, engineering, device fabrication and commercialization
Guest lecture - Prof. Emil List-Kratochvil, Humboldt-Universität zu Berlin
Published September 29, 2017
Speaker: Prof. Emil List-Kratochvil, Humboldt Universität zu Berlin
Date/Time: Wednesday, September 29, 2017, 04:30 PM - 05:30 PM
Location: TU Dresden, Walther-Hempel-Building, HEM 219 seminar room (second floor)
Topic: Hybrid Resistive Memory Elements: Fundamental Considerations and Emerging Device Applications
Marcus Richter wins the ACS Nano Poster Prize Award
Published September 5, 2017
Congratulations to cfaed PhD student Marcus Richter for being honored with one of three prestigious ACS Nano Poster Prize Awards at the ChinaNANO 2017 in Beijing, which was held between August 29-31. He received it for his poster on “Polycyclic Azomethine Ylides as Versatile Building Block for Unprecedented N-doped Nanographenes”. A total of over 800 posters were pitching at the conference. The prize was handed over by Prof. Paul S. Weiss (founding Editor-in-Chief of ACS Nano) during the closing session. Marcus Richter, who was supported by the cfaed Inspire Grant, visited the chairs of Prof. Carlos-Andres Palma, Prof. Shixuan Du and Prof. Hong-Jun Gao at the Institute of Physics at the Chinese Academy of Science in Beijing for two months.
ChinaNANO 2017 is intended to stimulate discussions on the forefront of research in nanoscience and nanotechnology. The conference will focus on carbon nanomaterials, inorganic nanomaterials and MOFs, self-assembly and soft nanomaterials, nanocatalysis, nano-composites and applications, energy nanotechnology, environmental nanoscience and nanotechnology, nanophotonics and plasmonics, 2D materials beyond graphene and nanodevices, nanocharacterization, standards and metrology, modeling and simulation of nanostructures, nanobiotechnology and nanomedicine, nanotechnology for bioimaging and diagnostics, safety and health of nanomaterials，printing of nanomaterilas and applications as well as optoelectronic nanomaterials and devices.
About ACS Nano
Published monthly, ACS Nano is an international forum for the communication of comprehensive articles on nanoscience and nanotechnology research at the interfaces of chemistry, biology, materials science, physics, and engineering. Moreover, the journal helps facilitate communication among scientists from these research communities in developing new research opportunities, advancing the field through new discoveries, and reaching out to scientists at all levels.
The 1st China-EU Graphene Flagship Bilateral Workshop on Graphene and 2D Materials was co-organized by Prof. Xinliang Feng in Beijing, China
Published July 7, 2017
Prof. Xinliang Feng was one of the co-organizers of the successful 1st China-EU-Graphene Flagship Workshop on Graphene and 2D Materials. The workshop took place in Beijing, China at the Chinese Academy of Sciences (IOP, CAS) from June 29th - July 2nd, 2017.
Guest lecture - Prof. Wei Zhang, University of Colorado Boulder, USA
Published July 7, 2017
Speaker: Prof. Wei Zhang, University of Colorado Boulder, USA
Date/Time: Wednesday, July 5, 2017, 11:00 AM - 12:30 PM
Location: TU Dresden, Walther-Hempel-Building, HEM 219 seminar room (second floor)
Topic: Molecular Architectures and Functional Materials through Dynamic Covalent Assembly
Hamburg Science Award 2017 goes to Klaus Müllen and Xinliang Feng
Published on June 27, 2017
Klaus Müllen of Max Planck Institute for Polymer Research (MPI-P) in Mainz and Xinliang Feng of Center for Advancing Electronics Dresden / Technische Universität Dresden will be awarded the Hamburg Science Award 2017, which this year is dedicated to the subject of energy efficiency. The Academy of Sciences and Humanities thus honours the two chemists’ research in the field of graphene research. This functional material, which – due to its various properties – has since its discovery in 2004 been considered as the material of the future, is especially suitable to be used in batteries and supercapacitors. [...]
Workshop "Chemistry of 2-Dimensional Materials" in Dresden
Published on June 23, 2017
This workshop unites internationally renowed experts to share their experiences in this field of research and serves as a plattform for joint discussions.
Prof. Xinliang Feng's & Prof. Klaus Müllen's book "Chemistry of Carbon Nanostructures" has been published
Published on June 23, 2017
Carbon Materials such as nanoparticles, fibres, adamantane- and graphene-like structures are widely used in science and engineering. Applications range from energy and gas storage to electronics and optical applications. The internationally renowned experts who contributed to this book discuss chemical aspects of carbon structures, their synthesis, functionalization and design strategies for defined applications.
Link: De Gruyter
π-Extended and Curved Antiaromatic Polycyclic Hydrocarbons
Published on June 13, 2017
To date, it remains a great challenge to develop the p-extended anti-aromatic polycyclic hydrocarbons (PHs) with more than 20 p-electrons. Moreover, the anti-aromatic PHs reported till now mainly adopt a planar p-conjugated carbon skeleton. In order to pursue the synthesis of novel p-extended and stable anti-aromatic PHs, Cfaed scientists at TU Dresden and collaborators reported the solution synthesis of air-stable 24 and 28 p-electron anti-aromatic PHs (1a and 1b) by laterally extending indeno[1,2-b]fluorene and fluoreno[3,2-b]fluorene, respectively. In addition, for the first time, a curved 48 p-electrons anti-aromatic molecule (1c) was synthesized. The X-ray crystallographic analysis confirms that while 1a and 1b manifest planar structures, 1c shows a curved p-conjugated carbon skeleton. The experimental results demonstrated that 1a, 1b and 1c represent a new type of air-stable, fully conjugated anti-aromatic PHs, which can be used as potential candidates in optoelectronic devices due to their narrow HOMO-LUMO energy gaps and excellent reversible electron transfer properties. The synthetic strategy towards anti-aromatic PHs by building five-membered rings from the ortho-substituted benzene units and the combination of cove-edge structures, can be applied to the construction of other air-stable p-expanded and curved anti-aromatic PHs as well as even helical graphene nanoribbons. The related works are published in J. Am. Chem. Soc.
For more details please click on the link: JACS
This work was financially supported by ERC grants on 2DMATER, the EC under Graphene Flagship (No. CNECT-ICT-604391), Center for Advancing Electronics Dresden (cfaed), European Social Fund and the Federal State of Saxony (ESF-Project “GRAPHD”, TU Dresden) and ERC Consolidator grant 648295 "GraM3".
Junzhi Liu, Ji Ma, Ke Zhang, Prince Ravat, Peter Machata, Stanislav Avdoshenko, Felix Hennersdorf, Hartmut Komber, Wojciech Pisula, Jan J. Weigand, Alexey A. Popov, Reinhard Berger, Klaus Müllen, Xinliang Feng*. J. Am. Chem. Soc. 2017, 139, 7513-7521.( ?J.L. and J.M. contributed equally to this work.)
Prof. Xinliang Feng receives ERC Proof of Concept Grant
Published on June 13, 2017
In May 2017 the European Research Council ERC awarded Proof of Concept Grants, each worth 150,000 €, to fifty one people - Prof. Dr. Xinliang Feng is one of the grant holders. The Proof of Concept grants can be used, for example, to establish intellectual property rights, investigate business opportunities or conduct technical validation.
Synthesis of Molecular Hydrogen: Novel Method Sets Benchmark for Platinum-free Electrocatalysts
Published on May 26, 2017
A paper from cfaed’s Chair for Molecular Functional Materials co-authored by researchers at universities and institutes in Germany, France and Japan has been published in Nature Communications on 17th May 2017. The paper titled “Efficient hydrogen production on MoNi4 electrocatalysts with fast water dissociation kinetics” describes a new approach to revolutionize the production of molecular hydrogen. This gas is considered to be one of the most promising energy carriers of the future.
Growing concern about the energy crisis and the seriousness of environmental contamination urgently demand the development of renewable energy sources as feasible alternatives to diminishing fossil fuels. Owing to its high energy density and environmentally friendly characteristics, molecular hydrogen is an attractive and promising energy carrier to meet future global energy demands. In many of the approaches for hydrogen production, the electrocatalytic hydrogen evolution reaction (HER) from water splitting is the most economical and effective route for the future hydrogen economy. To accelerate the sluggish HER kinetics, particularly in alkaline electrolytes, highly active and durable electrocatalysts are essential to lower the kinetic HER overpotential. As a benchmark HER electrocatalyst with a zero HER overpotential, the precious metal platinum (Pt) plays a dominant role in present H2-production technologies, such as water-alkali electrolysers. Unfortunately, the scarcity and high cost of Pt seriously impede its large-scale applications in electrocatalytic HERs.
Prof. Xinliang Feng’s team from the Technische Universität Dresden (Germany)/ Center for Advancing Electronics Dresden (cfaed), in collaboration with the University Lyon, ENS de Lyon, Centre national de la recherche scientifique (CNRS, France), the Tohoku University (Japan) and the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) (Germany), have reported a low-cost MoNi4 electrocatalyst anchored on MoO2 cuboids, which are vertically aligned on nickel foam (MoNi4/MoO2@Ni). MoNi4 nanoparticles are constructed in situ on the MoO2 cuboids by controlling the outward diffusion of Ni atoms. The resultant MoNi4/MoO2@Ni exhibits a high HER activity that is highly comparable to that of the Pt catalyst and presents state-of-the-art HER activity amongst all reported Pt-free electrocatalysts. Experimental investigations reveal that the MoNi4 electrocatalyst behaves as the highly active centre and manifests fast Tafel step-determined HER kinetics. Furthermore, density functional theory (DFT) calculations determine that the kinetic energy barrier of the Volmer step for the MoNi4 electrocatalyst is greatly decreased. The large-scale preparation and excellent catalytic stability provide MoNi4/MoO2@Ni with a promising utilization in water-alkali electrolysers for hydrogen production. Therefore, the exploration and understanding of the MoNi4 electrocatalyst provide a promising alternative to Pt catalysts for emerging applications in energy generation.
Efficient hydrogen production on MoNi4 electrocatalysts with fast water dissociation kinetics. J. Zhang, T. Wang, P. Liu, Z. Liao, S. Liu, X. Zhuang, M. Chen, E. Zschech, X. Feng* Nat. Commun.
This work was financially supported by the ERC Grant on 2DMATER and EC under Graphene Flagship (No. CNECT-ICT-604391).
Link: Nature Communications
Prof. Xinliang Feng wins the 2017 Small Young Innovator Award
Published on May 26, 2017
The Small Young Innovator Award recognizes outstanding, interdisciplinary scientific work in the development and fundamental understanding of nanoscience and nanotechnology by a young scientist or engineer. Prof. Feng is one of the two winners of the Small Young Innovator Award, receiving it for his important contributions to 2D nanomaterials.
The award ceremony took place during the "Small Science Symposium" in Hong Kong at the Hong Kong Polytechnic University on May 16, 2017.
Ultrafast Delamination of Graphite into High-Quality Graphene Using Alternating Currents
Published on May 5, 2017
Global progress in graphene research is expected to unlock a new era in the next generation of electronics. To bridge the gap between laboratory-scale study and commercial applications, mass production of high quality graphene is essential. Here Cfaed scientists at TU Dresden and collaborators demonstrate a scalable exfoliation strategy towards the production of graphene sheets that has excellent yield (ca. 75 %, 1-3 layers), low defect density (a C/O ratio of 21.2), great solution-processability and outstanding electronic property (a hole mobility of 430 cm2•V-1•s-1). By applying alternating currents, dual exfoliation at both graphite electrodes enables a high production rate exceeding 20 g h-1 in laboratory tests. As a cathode material for lithium storage, graphene-wrapped LiFePO4 particles deliver a high capacity of 167 mAh g-1 at 1 C rate after 500 cycles. The high-quality solution-processable exfoliated graphene holds great promise for a wide spectrum of applications, such as inkjet printing, solar cells and composites.
This work was financially supported by ERC grants on 2DMATER and UPGreen, the EC under Graphene Flagship (No. CNECT-ICT-604391).
Sheng Yang, Antonio Gaetano Ricciardulli, Shaohua Liu, Renhao Dong, Martin R. Lohe, Alfons Becker, Marco A. Squillaci, Paolo Samorì, Klaus Müllen*, Xinliang Feng*
Ultrafast Delamination of Graphite into High-Quality Graphene Using Alternating Currents
Angew. Chem. Int. Ed. 2017, 56, 1 - 8, DOI: 10.1002/anie.201702076
Angew. Chem.. 2017, 129, 1- 8, DOI: 10.1002/ange.201702076 (hot paper)
Link to: AngewChem
Honorable Mention for the 2017 IUPAC-SOLVAY International Award for Young Chemists
Published on April 5, 2017
The International Union of Pure and Applied Chemistry and Solvay announced the winners of the 2017 IUPAC-Solvay International Award for Young Chemists, presented for the best Ph.D. theses in the chemical sciences, as described in 1000-word essays.
There were 34 applications from individuals receiving their Ph.D. degrees from institutions in 19 countries. The award selection committee, chaired by Dr. Mark C. Cesa, IUPAC Past President, comprised members of the IUPAC Bureau and a senior science advisor from Solvay, all of whom have a wide range of experience in chemistry.
Dr. Junzhi Liu is one of the recipients of the Honorable Mention for the 2017 IUPAC-Solvay International Award for Young Chemists, which acknowledges the best PhD thesis in chemical science.
The recipients of Honorable Mention will receive a copy of the IUPAC History bookset.
Link to: IUPAC
cfaed Successfully Presented at 'Graphene2017' in Barcelona - Next Year's Conference Will be Held in Dresden
Published on April 4, 2017
With the support of the cfaed team, Prof. Xinliang Feng's Chair for Molecular Functional Materials was able to successfully present the Cluster with its own booth at the largest European graphene conference
in Barcelona. For four days, representatives of the areas atomic precision (Reinhard Berger), energy storage and transformation (Xiaodong Zhuang), and production and innovation (Martin Lohe) were in close
contact with numerous visitors.
Many questions about the properties and possible applications of graphene and nanographene strips were discussed. In the closing session of the conference, a big success could be publicly announced:
We are pleased to reveal that the 'Graphene 2018' will take place in Dresden!
Link to: Press release
Coordination Polymer Framework-Based On-Chip Micro-Supercapacitors with AC Line-Filtering Performance
April 4, 2017
On-chip micro-supercapacitors (MSCs) are important Si-compatible power source backups for miniaturized electronics, owing to their rapid energy-harvesting features, burst-mode power delivery,
and in particular the good compatibility with Si. However, current on-chip MSCs require harsh processing conditions (high-temperature fabrication, oxygen plasma and wet-chemistry etching, etc.),
and typically perform like resistors when filtering ripples from alternating current (AC). Therefore, the development of Si-compatible MSCs with facile fabrication procedure is an urgent task for
their practical applications.
Recently, Prof. Xinliang Feng, Dr. Enrique Cánovas, Dr. Xiaodong Zhuang firstly reported an on-chip MSC based on a coordination polymer framework (PiCBA) by using a facile layer-by-layer strategy. Owing to
the good carrier mobility (5 × 10-3 cm2•V-1•s-1) of PiCBA, strong interaction between PiCBA and patterned Au current collectors, and in-plane geometry, the as-fabricated MSCs delivered high specific capacitances
of up to 34.1 F•cm-3 at 50 mV•s-1, a volumetric power density of 1323 W•cm-3 and an energy density of 4.7 mWh•cm-3. Moreover, the fabricated MSCs exhibited typical AC line-filtering performance (-73° at 120 Hz)
with a short resistance-capacitance constant of ~0.83 ms, which is well comparable to the state-of-art MSCs. This study not only provides a general, easy method for the preparation of on-chip MSCs, but also
demonstrates the remarkable energy storage potential of coordination polymer frameworks.
Figure. a-c) Schematic illustration of LBL fabrication of PiCBA films on Au interdigital electrodes; e) Impedance phase angle on the frequency for the PiCBA-based microdevices; f) Impedance phase angle
on the frequency for the PiCBA-based microdevices; g) Calculated quantum capacitance based on the two bands crossing the Fermi level for zero disorder, and charge density of the lower band crossing the Fermi
level at the G point as well as close to the Brillouin zone boundary at X, namely k = (0.4, 0.0, 0.0).
C. Yang, K. S. Schellhammer, F. Ortmann, S. Sun, R. Dong, M. Karakus, Z. Mics, M. Löffler, F. Zhang, X. Zhuang,* E. Cánovas,* G. Cuniberti, M. Bonn, X. Feng*
Coordination Polymer Framework Based On-Chip Micro-Supercapacitors with AC Line-Filtering Performance
Angew. Chem. Int. Ed. 2017, 56, 3920-3924. [DOI: 10.1002/anie.201700679] [very important paper]
Link to: Angewandte Chemie
Guest lecture - Prof. Hossam Haick, Technion - Israel Institute of Technology, Israel
March 24, 2017
Speaker: Prof. Hossam Haick, Technion - Israel Institute of Technology, Israel
Date/Time: Tuesday, April 11, 2017, 09:30 am - 10:30 am
Location: TU Dresden, Walther-Hempel-Building, HEM 219 seminar room (second floor)
Topic: Novel Alliance between Advanced Materials and Volatile Biomarkers for Non-Invasive Medical Evaluation
Highly Stable Open-Shell Nanographenes with a Saddle-Shaped Geometry
February 16, 2017
Open-shell nanographenes (or polycyclic hydrocarbons) have attracted a great deal of interest because of their unique nonlinear optical, electronic and magnetic properties, making them promising candidates for organic electronic and spintronic devices. However, it is the intrinsic instability of the biradical species that limits the practicality of this research. The scientists from Dresden University of Technology (Prof. Xinliang Feng) reported the synthesis of the first example of highly stable open-shell nanographenes with a saddle-shaped p-conjugated geometry. The achieved saddle-shaped nanographenes exhibits an open-shell singlet biradical structure (biradical index: y = 0.69) in the ground state with a narrow optical energy gap of 0.92 eV. More importantly, the title nanographene displays excellent stability at air and sun light conditions, with the half-life time (t1/2) as long as 39 days. The synthetic concept reported in this work introduces new perspectives on the accessibility of high-spin graphene-like moleculae with a view towards potential materials applications in organic spintronics. The related works are published in Angewandte Chemie, for more details please click the link: http://dx.doi.org/10.1002/anie.201611689.
This work was financially supported by ERC grants on 2DMATER, the EC under Graphene Flagship (No. CNECT-ICT-604391), Center for Advancing Electronics Dresden (cfaed), European Social Fund and the Federal State of Saxony (ESF-Project “GRAPHD”, TU Dresden).
Literature: Ji Ma, Junzhi Liu*, Martin Baumgarten, Yubin Fu, Yuan-Zhi Tan, Karl Sebastian Schellhammer, Frank Ortmann, Gianaurelio Cuniberti, Hartmut Komber, Reinhard Berger, Klaus Müllen and Xinliang Feng*. Angew. Chem. Int. Ed. 2017, 56, DOI: 10.1002/anie.201611689.
Link to: Angewandte Chemie
Persulfurated Coronene: A New Generation of “Sulflower”
February 12, 2017
Currently, fully sulfur-substituted polycyclic aromatic hydrocarbons (PAHs) carrying fused disulfide bonds at the periphery have not yet been achieved. Here, Cfaed scientists at TU Dresden with collaborators report the first synthesis of a persulfurated PAH as a next-generation “sulflower.” In this novel PAH, disulfide units establish an all-sulfur periphery around a coronene core (C24S12). The structure, electronic properties, and redox behavior were investigated by microscopic, spectroscopic and electrochemical methods and supported by density functional theory (DFT). The sulfur-rich character of persulfurated coronene renders it a promising cathode material for lithium-sulfur batteries, displaying a high capacity of 520 mAh g-1 after 120 cycles at 0.6 C with a high-capacity retention of 90%. The protocol established in this work offers unique access to larger PAHs and graphene (or graphene nanoribbons) with persulfurated edges and paves the way toward promising applications in OFETs, OPVs, energy, and superconductor-related areas.
Link to: JACS
December 6, 2016
Smart micro-/nano-devices or stimuli-responsive devices have attracted substantial attention due to a wide range of needs for smart modern electronics. Nevertheless, it remains a great challenge to integrate various kinds of stimuli into modern functional devices without sacrificing the device performance, most probably due to the poor compatibility among those stimuli, active materials, and processing technologies. The scientists from Dresden University of Technology (Prof. Xinliang Feng) and Chemnitz University of Technology (Prof. Oliver G. Schmidt) reported the fabrication of the first stimulus-responsive micro-supercapacitor (SR-MSC) with ultrahigh volumetric energy density (20 mWh cm-3 at 235 W cm-3) and reversible electrochromic effect by employing vanadium pentoxide and electrochemical exfoliated graphene-based hybrid nanopaper and viologen as electrode and stimulus-responsive material, respectively. The fabricated high performance SR-MSCs offer new opportunities for intuitively observing the working state of energy devices without the aid of extra equipment and techniques.
This work was financially supported by the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden” (cfaed) and the Initiative and Networking Fund of the German Helmholtz Association, Helmholtz International Research School for Nanoelectronic Networks NanoNet (VH-KO-606), ERC Grant on 2DMATER, UP-GREEN, and EU Graphene Flagship.
Literature:  Panpan Zhang, Feng Zhu, Faxing Wang, Jinhui Wang, Renhao Dong, Xiaodong Zhuang,* Oliver G. Schmidt, and Xinliang Feng*, Stimulus-Responsive Micro-Supercapacitors with Ultrahigh Energy Density and Reversible Electrochromic Window, Adv. Mater. 2017, in press. [DOI: 10.1002/adma.201604491].
Wafer-sized multifunctional polyimine-based two-dimensional conjugated polymers with high mechanical stiffness
November 16, 2016
Two-dimensional (2D) soft materials have attracted increasing attention in chemistry, materials science, nanotechnology and biology due to their fascinating optical, electrical, mechanical and magnetic properties derived from the reduction of dimensions. One of the key challenges in 2D materials is to go beyond graphene, a prototype 2D polymer (2DP), and to synthesize its organic analogues with structural control at the atomic- or molecular-level. Here, Cfaed scientists at TU Dresden, reported the successful preparation of porphyrin containing monolayer and multilayer crystalline conjugated 2DPs through the Schiff-base polycondensation reaction at an air-water and liquid-liquid interface. The monolayer 2DP has a thickness of 0.7 nm with a lateral size of 4-inch wafer, and has a Young’s modulus of 267±30 GPa, which is on the same order of graphene (200-1000 GPa). The 2DP has an optical band gap of 1.4 eV and the monolayer 2DP can function as an active semiconducting layer in a thin film transistor and electrocatalyst towards water splitting. This work opens the door for the synthesis of functional 2DPs using reversible polycondensation reaction, which may pave the way for the rational synthesis of 2D organic soft materials for next generation electronics and energy-related applications.
Link to: Nature Communications
EU Graphene Flagship Meeting
November 3 & 4, 2016
On November 3rd and 4th a meeting of the EU Graphene Flagship with 31 participants from 18 different European institutes and companies took place at TU Dresden. The purpose of the meeting of the Flagship Work Package 13 on Functional Foams and Coatings led by Professor Xinliang Feng was to discuss recent progress and future perspectives in the field of graphene and related 2D materials. The special focus was their use in coatings, thin films and porous structures like foams and membranes for applications such as energy storage and conversion, catalysis, water remediation and environmental protection.
CFAED Distinguished Lecture Series - Nobel Prize Laureate Professor Sir Konstantin S. Novoselov FRS, University of Manchester, UK
September 16, 2016
Speaker: Professor Sir Konstantin S. Novoselov FRS, University of Manchester, UK
Date/Time: September 16, 2016, 4:00 pm - 5:00 pm
Location: TU Dresden, Dülfersaal
Topic: Materials in the Flatland
Atom-thick solution to energy storage conundrum
September 12, 2016
Sheets of carbon an atom thick could soon double the amount of electricity stored in smartphone batteries, researchers believe, as 2D materials present a picture of the future of energy storage.
The transition from fossil fuels to renewable energy, combined with the increasing power of today’s portable devices, calls for cheap materials that can store electricity on an unprecedented scale. Researchers are exploring the extraordinary characteristics of two-dimensional nanomaterials to achieve this goal. According to Professor Xinliang Feng, at the Technical University Dresden, Germany, confining the thickness of materials to nanoscopic dimensions can endow them with exciting physical and chemical properties. This is because, at small scales, electrons obey the exotic laws of quantum mechanics. They spread like waves, exist in multiple places at the same time, and engage in all manner of activities that contradict our experience in the macroscopic world. Prof. Feng is trying to put quantum effects to work in cheaper and more powerful energy storage technologies. Already atomically thin layers of carbon, known as graphene, are helping researchers squeeze more electricity out of conventional lithium-ion batteries. The negative electrode of these batteries is commonly made of bulk carbon. Each lithium ion stores energy by fixing itself to this electrode, typically by bonding with six carbon atoms on its surface. Because graphene is so thin, the lithium ions only need three carbon atoms to hold them in place. This doubles the amount of energy that can be stored in a given size of battery.
Read full article: Horizon - The EU Research & Innovation Magazine
Joint Kick-Off Event ESF „Graphene Center Dresden“ and 2.5D-Path of the Center for Advancing Electronics Dresden (cfaed)
September 07, 2016
On September 7th, the official start of the ESF-supported Young Researcher Group ‘Graphene Center Dresden’ (GraphD) took place at TU Dresden. In addition, the initiation of a new path dedicated to two dimensional materials within the Cluster of Excellence Center for Advancing Electronics Dresden (cfaed) was celebrated with the participation of very distinguished guests. The Graphene Center Dresden is an ESF Young Researcher Group, funded by the European Social Fund (ESF), with strong collaboration of many chairs within TU Dresden under the supervision of cfaed’s Strategic Professorship ‘Molecular Functional Materials’ of Prof. Xinliang Feng. Cooperation partners include, e.g., Prof. Sibylle Gemming, Prof. Alexander Eychmüller, Prof. Stefan Kaskel, Prof. Karl Leo, Prof. Stefan Mannsfeld, Prof. Michael Schröter, Prof. Gotthard Seifert as well as Prof. Gianaurelio Cuniberti. All hold important functions within cfaed as research path leaders and principal investigators. With this joint competence, TU Dresden will emerge as one of the most important European actors in the field of the “wonder material” graphene and related two-dimensional materials. These one-atom thin materials exhibit outstanding physical properties, which render them promising candidates for application in various fields of electronic and energy applications as well as, for instance, novel lubricants. Meanwhile, graphene has been implemented in the first industrial applications. This is also one of the core competences of the Graphene Center Dresden: The close relationship to industrial partners is an elementary part of its strategy. The recently started ESF young researcher group ‘GraphD’ is an important milestone, funded by the European Social Fund (ESF). GraphD started on July 1st and consists of three postdocs, six PhD students, and the research group leader Dr. Reinhard Berger. Aims of the group are, amongst others, to attract the world’s most renowned young scientists in the field, train outstanding experts for Saxony’s industry, enforce the innovation potential of local companies, and to efficiently complement the regional cluster of ‘Silicon Saxony’. The Center for Advancing Electronics Dresden currently prepares a proposal within the ‘Excellence Strategy’ of the German Federal and State governments. It’s program will be extended to include research of two-dimensional materials within a new ‘2.5D-path’.
All photos: cfaed / Katharina Knaut
Professor Xinliang Feng
Technische Universität Dresden
Chair of Molecular Functional Materials
Center for Advancing Electronics Dresden (cfaed)
Phone: +49 351 463-43251
Center for Advancing Electronics Dresden (cfaed)
Phone: +49 (0)351 463 42847
Two-Dimensional Mesoscale-Ordered Conducting Polymers
September 07, 2016
Despite the availability of numerous two-dimensional (2D) materials with structural ordering at the atomic or molecular level, direct construction of mesoscale-ordered superstructures within a 2D monolayer remains an enormous challenge. Here, cfaed scientists at TU Dresden with collaborators, report the synergic manipulation of two types of assemblies in different dimensions to achieve 2D conducting polymer nanosheets with structural ordering at the mesoscale. The resulting polyaniline nanosheets feature mesoscale-ordered hexagonal pore arrays, tunable morphologies and pore sizes, large specific surface area as well as anisotropic and record-high electrical conductivity. Such moldable approach creates a new family of mesoscale-ordered structures as well as opens avenues to the programmed assembly of multifunctional materials.
Link to: Angewandte Chemie Int. Ed.
Highlighted by Nature Reviews Materials
Synthesis of NBN-type Zigzag-Edged Polycyclic Aromatic Hydrocarbons: 1,9-Diaza-9a-boraphenalene as a Structural Motif
August 31, 2016
A novel class of dibenzo-fused 1,9-diaza-9a-boraphenalenes featuring zigzag edges with a nitrogen-boron-nitrogen bonding pattern named NBN-dibenzophenalenes (NBN-DBPs) has been synthesized. Alternating nitrogen and boron atoms imparts high chemical stability to these - else very reactive -zigzag-edged polycyclic aromatic hydrocarbons (PAHs). Upon oxidation, an open-shell intermediate is formed corroborated by spectroscopic calculations and in-situ spectroelectrochemistry. The oxidized nitrogen-boron-nitrogen subunit is isoelectronic to the pristine carbon zigzag periphery but also positively charged. This new synthetic strategy represents an efficient pathway towards NBN-doped zigzag-edged graphene nanoribbons.
Prof. Xinliang Feng has served as the organizer of the Graphene Flagship EU-Korea Workshop on Graphene and related 2D Materials
August 16, 2016
Prof. Xinliang Feng has served as the organizer of the Graphene Flagship EU-Korea Workshop on Graphene and related 2D Materials. The workshop took place in Copenhagen, Denmark from August 15 - 16, 2016. The purpose of the EU-Korea workshop is to exchange experiences, practices and ideas related to the current and emerging topics associated with the basic chemistry approach, materials synthesis, application development and commercialisation for graphene and related 2D materials. In addition, the aim is to explore further possibilities for collaborative research opportunities between researchers in Europe and Korea. This workshop is a follow up of the first EU-Korea workshop held in Busan (Republic of Korea) in 2015.
Chemical approaches to 2D materials
August 12, 2016
[...] Issue 29/2016 of Advanced Materials is a special issue of on chemical approaches to 2D materials, guest edited by Paolo Samorì, Vincenzo Palermo, and Xinliang Feng, which provides a state-of-the-art description of the most enlightening results regarding various chemical approaches to 2D materials, written by some among the most creative scientists in the field.[...]
Link to: Materials Views
Guest lecture - Prof. josef Michl, University of Colorado Boulder, USA
August 12, 2016, 10:00 pm - 11:30 pm, CHE091
Speaker: Prof. Josef Michl (University of Colorado Boulder, USA)
Date/Time: August 12, 2016; 10:00 am - 11:30 am
Location: TUD, CHE091, New Chemistry Building
Topic: Direct Alkylation of Gold Surfaces with Solutions of Organometallics
A New Bowl-shaped Subunit of Fullerene C70
June 29, 2016
Total synthetic approaches of fullerenes are a holy grail for organic chemistry. So far, the main attempts have been focused on the synthesis of the buckminsterfullerene C60. In contrast, access to subunits of the homologue C70 remains challenging. Here, we demonstrate an efficient bottom-up strategy towards a novel bowl-shaped polycyclic aromatic hydrocarbons (PAH) C34 with two pentagons. This PAH represents a subunit for C70 and also of other higher fullerenes. The bowl-shaped structure was unambiguously determined by X-ray crystallography. Especially, a bowl-to-bowl inversion for a C70 fragment in solution was investigated by dynamic NMR analysis, showing a bowl-to-bowl inversion energy (ΔG‡) of 16.7 kcal mol-1, which is further corroborated by DFT calculations.
Link to: ACS Publications JACS
Guest lecture - Prof. Felix R. Fischer, University of California Berkeley
May 25, 2016, 1:30 pm - 3:00 pm, HEM 219
Speaker: Prof. Felix R. Fischer (University of California Berkeley)
Topic: Teaching Polymers the Meaning of Life & Quantum Confinement in Graphene Nanostructures
Guest lecture - Prof. Di Zhang
May 10, 2016
Speaker: Prof. Di Zhang (Shanghai Jiaotong University)
Topic: Bioinspired Materials Templated from Nature Species
Topical Workshop on Graphene and Nanoscience held in Dresden
published April 25 2016
On Monday, April 25, 2016 Prof. Xinliang Feng (cfaed / Chair for Molecular Functional Materials) welcomed a delegation of 20 people from the Chinese Graphene Industrial Alliance (CGIA) in Dresden. A workshop on graphene and nanoscience was organized including the top scientific and industrial experts from TU Dresden, Leibniz Institute for Polymer Research Dresden (Leibnitz-IPF), and Chinese representatives from industry and science. TUD’s vice-rector for research Prof. Gerhard Rödel held the welcoming speech and introduced the university to the guests from China. During the workshop, Prof. Karl Leo (Chair for Optoelectronics) represented the Center for Advancing Electronics Dresden (cfaed) and Institute for Applied Photophysics (IAPP) and Dr. Martin Lohe (Chair for Molecular Functional Materials) informed about the latest developments in graphene production. The delegation of the CGIA informed about their activities in regards to graphene commercialization. Since China has emerged to be a key player not only in terms of industrial aspects but also regarding the outstanding scientific development, the purpose of the workshop was to lay the foundations for the future cooperation between TU Dresden and China.
Link to: https://www.chm.tu-dresden.de
Graphene nanoribbons: it's all about the edges
published 24 Mar 2016
When electrons spin differently Graphene nanoribbons: it's all about the edges.
As reported by the journal Nature in its latest issue, researchers from Empa, the Max Planck Institute in Mainz and the Technical University of Dresden have for the first time succeeded in producing graphene nanoribbons with perfect zigzag edges from molecules. Electrons on these zigzag edges exhibit different (and coupled) rotational directions ("spin"). This could make graphene nanoribbons the material of choice for electronics of the future, so-called spintronics.
Graphene slides smoothly across gold
published 26 Feb 2016
Graphene, a modified form of carbon, offers versatile potential for use in coating machine components and in the field of electronic switches. An international team of researchers led by physicists at the University of Basel, and including TU Dresden (Dr. Andrea Benassi and Dr. Xinliang Feng) have been studying the lubricity of this material on the nanometer scale. Since it produces almost no friction at all, it could drastically reduce energy loss in machines when used as a coating, as the researchers report in the journal Science. In future, graphene could be used as an extremely thin coating, resulting in almost zero energy loss between mechanical parts. This is based on the exceptionally high lubricity—or so-called superlubricity—of modified carbon in the form of graphene. Applying this property to mechanical and electromechanical devices would not only improve energy efficiency but also considerably extend the service life of the equipment. Fathoming out the causes of the lubricant behavior An international community of physicists have studied the above-average lubricity of graphene using a two-pronged approach combining experimentation and computation. To do this, they anchored two-dimensional strips of carbon atoms—so-called graphene nanoribbons—to a sharp tip and dragged them across a gold surface. Computer-based calculations were used to investigate the interactions between the surfaces as they moved across one another. Using this approach, the research team is hoping to fathom out the causes of superlubricity; until now, little research has been carried out in this area. By studying the graphene nanoribbons, the researchers hope to learn about more than just the slip behavior. Measuring the mechanical properties of the carbon-based material also makes sense because it offers excellent potential for a whole range of applications in the field of coatings and micromechanical switches. In future, even electronic switches could be replaced by nanomechanical switches, which would use less energy for switching on and off than conventional transistors. The experiments revealed almost perfect, frictionless movement. It is possible to move graphene nanoribbons with a length of 5 to 50 nanometers using extremely small forces (2 to 200 piconewtons). There is a high degree of consistency between the experimental observations and the computer simulation. A discrepancy between the model and reality appears only at greater distances (five nanometers or more) between the measuring tip and the gold surface. This is probably because the edges of the graphene nanoribbons are saturated with hydrogen, which was not accounted for in the simulations. "Our results help us to better understand the manipulation of chemicals at the nano level and pave the way for creating frictionless coatings," write the researchers.
Linkt to: www.science.org
Patterning two-dimensional free-standing surfaces with mesoporous conducting polymers
published 30 Nov 2015
The ability to pattern functional moieties with well-defined architectures is highly important in material science, nanotechnology and bioengineering. Although two-dimensional surfaces can serve as attractive platforms, direct patterning them in solution with regular arrays remains a major challenge. Here, cfaed scientists at TU Dresden with collaborators, developed a versatile route to pattern two-dimensional free-standing surfaces in a controlled manner assisted by monomicelle close-packing assembly of block copolymers, which is unambiguously revealed by direct visual observation. This strategy allows for bottom-up synthesis of two-dimensional mesoporous conducting polymer nanosheets with adjustable mesopores on various functional free-standing surfaces, including two-dimensional graphene, molybdenum sulfide, titania nanosheets, and even on one-dimensional carbon nanotubes. This approach will shed light on developing solution-based soft patterning of given interfaces towards bespoke functions.
Link to: http://www.nature.com
Prof. Xinliang Feng Raises "Proof of Concept" Sponsorship from European Research Council
published 24 Nov 2015
Two scientists of TU Dresden succeeded in the second call for proposals of the European Research Council, “Proof of Concept Grants”. One of them is cfaed's Strategic Professor Xinliang Feng who has been honored for his project concerning electrochemical delamination of graphite. The honored scientists will now receive a sponsorship up to 150.000 Euros, which will contain a study about the viability of commercial utilization of the excellent research results. To apply for the sponsorship it was required that the scientists and projects had already been promoted by ERC. With the 'Proof of Concept Grant' the ERC wants to make a contribution to growth and innovation in the European Union.
Read this news in German on the page of Saxony Liaison Office Brussels
"Nanocarbons for Advanced Energy Conversion" Volume 2 edited by Prof. Xinliang Feng
published 22 Oct, 2015
Wiley has published the book "Nanocarbons for Advanced Energy Conversion" which has been edited by Prof. Xinliang Feng. The book is the volume 2 of the book series on nanocarbons for advanced applications.
Link to: http://eu.wiley.com
Radical assisted electrochemical exfoliation
published 17 Oct, 2015
Despite the intensive research efforts devoted to graphene fabrication over the last decade, the production of high-quality graphene on a large scale, at an affordable cost and in a reproducible manner still represents a great challenge. Cfaed scientists with collaborators report a novel method based on the controlled electrochemical exfoliation of graphite in aqueous ammonium sulfate electrolyte to produce graphene in large quantities and with outstanding quality. The developed exfoliation method results in large graphene sheets (5-10 µm on average), which exhibit outstanding hole mobilities (~405 cm2 V-1 s-1), very low Raman ID/IG ratios (below 0.1), and extremely high carbon to oxygen (C/O) ratios (~25.3). Moreover, the graphene ink prepared in dimethylformamide qualifies this material for intriguing applications such as transparent conductive films and flexible supercapacitors. In general, this robust method for electrochemical exfoliation of graphite offers great promise for the preparation of graphene that can be utilized in industrial applications to create integrated nanocomposites, conductive or mechanical additives as well as energy storage and conversion devices.
Link to: http://pubs.acs.org
Highly Cited Researcher
published 21 Sept 2015
Prof. Dr. Xinliang Feng was listed as highly cited researcher in 2015 (published by Thompson Reuters) for both categories - chemistry and materials science.
Link to: http://highlycited.com/
Temperature-Dependent Multidimensional Self-Assembly of Polyphenylene-Based “Rod-Coil” Graft Polymers
published 7 Sept 2015
cfaed scientists at TU Dresden with collaborators demonstrate a novel type of “rod−coil” graft copolymer containing a polyphenylene backbone linked with poly(ethylene oxide) (PEO) side chains. Such graft copolymers manifest unprecedented temperature-dependent one-dimensional (1D) and two-dimensional (2D) self-assembly in solution. At 20°C, which is higher than the crystallization temperature (Tc) of the PEO chains, the achiral graft copolymers self-organize into nanoribbons that twist into 30 μm ultralong helices with controlled pitch depending on the grafting ratio of the PEO chains. At 10°C, which is lower than the Tc, quadrangular multilayer sheets of over 10 μm in lateral size are obtained. This work presents the first example of controlled self-assembly of graft polymers into 1D helix and 2D sheet superstructures. Such graft polymers provide new opportunities for the controlled preparation of 1D helix and 2D superstructures as well as offer a new system for the fundamental studies on the self-assembly of conjugated polymers, including morphological control, thermodynamics and kinetics, potential applications, etc.
View Publication online: http://pubs.acs.org/doi/abs/10.1021/jacs.5b07487
Synthetic two-dimensional conjugated supramolecular polymers (2DSPs) open new application in electrocatalysis
published 7 Sept 2015
Two-dimensional polymers and supramolecular polymers refer to laterally infinite, one monomer-unit thick, free-standing network with a defined internal periodicity based on covalent and non-covalent bond, respectively. They represent a new class of artificially created 2D materials with a manifold of promises in electronics, membrane technology, catalysis, sensing, and energy storage and conversion. Here, cfaed scientists at TU Dresden, reported the synthesis of a large-area (mm2) crystalline 2DSP with a thickness of ∼ 0.7 nm, comprising triphenylene-fused nickel bis(dithiolene) complexes, at an air/water interface of Langmuir-Blodgett trough under ambient conditions. Such 2DSP, processed on a glassy carbon electrode, exhibited excellent electrocatalytic activity for hydrogen evolution reaction from water with a Tafel slope of 80.5 mV decade-1 and an operating overpotential of 333 mV at 10 mA cm-2, which are superior to those of carbon nanotube (CNT)-supported molecular catalysts and heteroatom-doped graphene catalysts. This work opens the door for developing large-area, free-standing 2D organic materials consisting of immobilized molecular catalysis as novel electrode materials bearing functions in energy technologies.
cfaed Seminar Series: Minisymposium on Graphene Materials
published 9 Jul 2015
On Wednesday, 15 July 2015, 15:00 - 17:00 we will hold a Minisymposium on Graphene Materials.
Beginning at 3 p.m. Prof Hui-Ming Cheng (Chinese Academy of Sciences) is going to give a talk titled “Graphene Materials: Large-Scale Fabrication and Application Explorations”.
Beginning at 4 p.m., Prof. Shi-Zhang Qiao (University of Adelaide, Australia) is going to give a talk titled “Metal-free and Non-precious Metal Materials for Energy-relevant Electrocatalytic Processes”.
Location: TU Dresden, New Chemistry Building, Lecture Theatre CHE S89, Bergstraße 66, 01069 Dresden
cfaed Seminar Series: Prof. Maurizio Prato
published 9 Jul 2015
We are happy to welcome Prof. Maurizio Prato (Università degli Studi di Trieste, Italy) on 13 July 2015 for a talk at our chair! Prof. Prato will speak about "Synergies between chemistry and nanotechnology: applications to neurosciences and energy".
Time: 4 pm
Location: TU Dresden, Hempel-Building, Seminar Room HEM 219 , Mommsenstraße 4 , 01069 Dresden
See abstract and short CV / download it: 20150713_cfaedSeminarSeries_Prato.pdf (158.2 KiB)
Fellow of the Royal Society of Chemistry
published 26 Nov 2014
In November 2014, Prof. Dr. Xinliang Feng has been appointed a Fellow of the Royal Society of Chemistry, UK. The honor is given to researchers who have made outstanding contributions to the advancement of chemical science.
The Royal Society of Chemistry has more than 49,000 members worldwide. The largest chemical society in Europe, the organization works to promote the development, practice and application of the chemical sciences across the world. In particular, the society encourages the participation of students and young people in chemistry.
New Certificate: "Highly Cited Researcher"
published Oct 2014
Prof. Xinliang Feng appears in the 2014 “highly cited researcher” list published by Thompson Reuters. This prestigious list includes scientific researchers whose publications have been cited most often in academic journals over the past decade and rank among the top 1 % most cited for their subject field and year of publication. Those listed are identified as being among the world’s leading scientific minds, along with the universities and institutions which employ them.