Environmentally friendly nanocrystal materials for optoelectronic applications (GreenDots)

Environmentally friendly and sustainable energy production is one of the greatest tasks of our time in order to meet the challenges of climate change and the increasing global energy demand. In addition to the classic photovoltaic modules made of silicon, new materials and technologies have emerged in recent years as alternatives that enable transparent, flexible and lightweight modules.

In particular, solar cells based on lead-halide perovskites and nanocrystals containing heavy metals have recently experienced considerable increase in their power conversion efficiencies and could open up these new areas of application. However, the high concentration of toxic and environmentally harmful elements such as lead or cadmium in these solar cells makes it questionable to what extent widespread use is even possible against the background of EU-wide directives limiting such harmful compounds. Moreover, the use of these toxic materials could become a significant issue at their end of life, when the modules would need to be disposed of, potentially harming both the environment and the society.

Basis for the production of efficient solar cells and light sensors

The GreenDots research project funded by BMBF focuses on the production and application of nanocrystalline materials, so-called quantum dots, which do not require the usual heavy metals such as lead or cadmium and are therefore more environmentally friendly. By varying the chemical synthesis conditions, the composition and size of the quantum dots can be adjusted, thus tuning the optical and electronic properties of the semiconducting nanomaterials to fit the desired application. After transferring the nanocrystals into concentrated, stable dispersions (inks), the fabrication of high-quality thin films is investigated using solution-based deposition and printing techniques. These processes, in turn, form the basis for the fabrication of efficient solar cells and sensitive light sensors.

Beyond the focus on increasing the performance and efficiencies of the devices, the project also investigates the reliability and stability of the materials and solar cells. To ensure that the production of these nanomaterials itself is also environmentally friendly, the focus within the research project is on the adaptation of environmentally compatible starting materials and solvents in the syntheses, a minimization of resource and energy consumption in the production and processing, as well as on a possible recyclability of the nanocrystals from disused components. Based on these data, the entire life cycle of the electronic components will be analyzed in terms of resource use and environmental impact in order to quantify and evaluate the economic added value of this technology at an early stage. This research project thus makes an important contribution to the development of materials for high-performance photovoltaics that conserve resources and protect the environment.

Main work packages

The research project is roughly divided into four interdisciplinary fields of work:

1 - Materials synthesis

  • Development of suitable synthesis routes for heavy metal-free nanocrystals
  • Control of composition, size and physical properties
  • Generation of stable, concentrated nanocrystal dispersions (inks)
  • Use of environmentally friendly starting materials and solvents
  • Reduction of resource and energy consumption
  • Scaling of syntheses to industrial scales

2 - Coating processes

  • Deposition of high quality layers of variable thickness while preserving the optical and electronic properties of the nanomaterials
  • Film formation by zone coating, printing and spraying processes for easier transferability to industrial scales
  • Nanostructuring for better charge carrier extraction in the later components

3 - Solar cells & sensors

  • Fabrication of efficient solar cells with the nanocrystals
  • Scaling from laboratory scale to prototypes on flexible substrates
  • Fabrication of sensitive photodiodes for the detection of visible and near-infrared light

4 - Environmental compatibility and recyclability

  • Investigation and improvement of impact, device stability and reliability
  • Evaluation of environmental performance and quantification of resource consumption
  • Determination of the recyclability and reusability of the materials
Industry orientation

The project is supported by three industrial partners who provide expertise in material development, film formation processes and component manufacturing. By setting clear targets in terms of material quality, properties of the thin films and the component parameters to be achieved, we want to ensure early transferability of the scientific results to the industrial scale and subsequent use of the project results.

logo avantama

Avantama AG, Stäfa, Switzerland: high-tech materials for the electronics industry, in particular nanocrystal dispersions


logo senorics

Senorics GmbH, Dresden, Germany: optical near-infrared sensors for mobile electronics


logo epishine

Epishine AP, Linköping Sweden: flexible solar cells for indoor applications

Project overview

Project title Umweltfreundliche Nanokristall-Materialien für optoelektronische Anwendungen (GreenDots)
Funding institution: Federal Ministry of Education and Research (BMBF)
Funding scheme: „NanoMatFutur“-Nachwuchsgruppen – Themenfeld Energietechnik
Industry patrons & project partners
Project start: 02 / 2022
Project period: 2022 - 2027
Funding reference number:

03XP0422 - Förderkatalog