cfaed Seminar Series
Prof. Alexander Sinitskii , University of Nebraska – Lincoln, Lincoln, NE, USA
Atomically Precise Graphene Nanoribbons: From Synthesis to Applications
15.06.2018 (Friday) Walther-Hempel-Building, Seminar Room HEM 219 , Mommsenstr. 4 , 01069 Dresden
Time: 13:00 - 14:30
Atomically precise graphene nanoribbons (GNRs) are at the forefront of nanocarbon research and hold great promise for electronic and optoelectronic applications. Theoretical studies have shown that narrow GNRs possess interesting electronic and magnetic properties that strongly depend on the nanoribbon’s width and edge structure. GNRs with different structures can be synthesized with atomic precision and fine-tuned properties by coupling properly designed molecular precursors and planarization of the resulting polymers. In this talk, I will discuss our efforts on design and synthesis of new atomically precise GNRs. First, I will describe a scalable bottom-up solution approach for atomically precise GNRs that is based on Yamamoto coupling of pre-synthesized molecular precursors followed by cyclodehydrogenation using Scholl reaction. This approch can be applied to the synthesis of a variety of GNRs, including pristine and nitrogendoped GNRs with the chevron structure. Then, I will demonstrate that the electrical conductivity of the chevron GNRs (cGNRs) can be improved by their lateral extension. The new laterally extended chevron GNRs (eGNRs) can be synthesized in solution as well as by on-surface techniques. The cGNR and eGNR units can also be combined into GNR heterojunctions. Finally, I will discuss a procedure for processing solution-synthesized GNRs into uniform thin films. The eGNR films were employed in gas sensors that showed very high responsivity to low molecular weight alcohols compared to similar sensors based on benchmark graphitic materials, such as graphene and graphene oxide. These sensors can by employed in an electronic nose system that can reliably recognize analytes of nearly the same chemical nature, such as methanol and ethanol. Overall, this talk will demonstrate the entire path from designing new atomically precise GNRs with improved properties to their bottom-up synthesis, characterization, processing and implementation in electronic devices.
Alexander Sinitskii received his B.S., and Ph.D. degrees in Materials Science from Moscow State University. After postdoctoral studies at Rice University in Houston, TX he moved to the University of Nebraska – Lincoln, where he is currently an Associate Professor of Chemistry. His research program is addressing the synthesis and properties of low-dimensional materials with potential applications in nanoelectronics, chemical sensing and energy storage. Sinitskii has published over 100 papers in peer-reviewed journals and is a co-inventor on 8 patents. He received several awards for his research and teaching, including a 2015 NSF CAREER Award and a 2017 UNL College of Arts and Sciences Distinguished Teaching Award.