EU funding strengthens solar cell research at HZB
Ultra-high vacuum system in the Energy Materials In-Situ Lab (EMIL) that will combine industry-relevant deposition tools with a suite of complementary advanced characterization methods. © R.G. Wilks
Marcus Bär and his team are participating in two international projects being funded under the EU Horizon 2020 research programme. Both research projects are concerned with development and optimisation of high-efficiency thin-film solar cells based on chalcopyrites (“Sharc 25") and kesterites (“SWInG”). These two projects will together bring in about 900,000 EUR of additional research funding for solar cell research.
The two projects, Sharc25 and SWInG, will be funded under the EU’s Low-Carbon Energy section. “The advanced material characterisation at HZB will focus on the interface characteristics of solar cell structures. Particularly, the complementarity of the suite of instruments at the newly established EMIL lab at BESSY II will benefit this research”, explains Prof. Marcus Bär, who heads the Young Investigator Group - Interface Design at HZB.
“Sharc25" stands for “Super High-Efficiency Cu(In,Ga)Se2 Thin-Film Solar Cells Approaching 25%”. The project will focus on pushing the performance of Cu(In,Ga)Se2 (CIGSe) thin-film solar cells towards 25 % conversion efficiency, which is considerably higher than the efficiency of market-dominating polycrystalline silicon cells. Achieving this level of efficiency would provide a significant competitive advantage for the European thin film PV industry. The research project will be coordinated by the Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) and involves research partners from seven European countries. The project funding is 6.15 million EUR in total, of which 450,000 EUR is allocated to HZB. “We will be systematically investigating the layer stacks, particularly focusing on understanding the properties and processes at the interfaces. Optimising the interface behaviour is a fundamental prerequisite for driving the efficiency towards its theoretical limit”, says Bär.
SWInG (Development of Thin-Film Solar Cells based on Wide Band-Gap Kesterite Absorbers) is to receive 3.8 million EUR and will be coordinated by imec (Interuniversity Micro-Electronics Centre/Belgium) and includes partners from the Netherlands, France, Germany, and Sweden. 450,000 EUR are allocated to HZB. The objective of the research is to develop inexpensive, dependable tandem solar cells that have the potential of converting more than 30% of sunlight into electricity. The wide band-gap solar cell absorbers necessary for this will be achieved by modifying the composition of the kesterite. “Kesterite absorber layers are desirable, because they consist of Earth-abundant elements. In addition, the band gap can be adjusted by varying the composition of the material, matching it to the requirements of the tandem solar cell”, explains Bär.
- Battery research with the HZB X-ray microscopeNew cathode materials are being developed to further increase the capacity of lithium batteries. Multilayer lithium-rich transition metal oxides (LRTMOs) offer particularly high energy density. However, their capacity decreases with each charging cycle due to structural and chemical changes. Using X-ray methods at BESSY II, teams from several Chinese research institutions have now investigated these changes for the first time with highest precision: at the unique X-ray microscope, they were able to observe morphological and structural developments on the nanometre scale and also clarify chemical changes.
- BESSY II: New procedure for better thermoplasticsBio-based thermoplastics are produced from renewable organic materials and can be recycled after use. Their resilience can be improved by blending bio-based thermoplastics with other thermoplastics. However, the interface between the materials in these blends sometimes requires enhancement to achieve optimal properties. A team from the Eindhoven University of Technology in the Netherlands has now investigated at BESSY II how a new process enables thermoplastic blends with a high interfacial strength to be made from two base materials: Images taken at the new nano station of the IRIS beamline showed that nanocrystalline layers form during the process, which increase material performance.
- Hydrogen: Breakthrough in alkaline membrane electrolysersA team from the Technical University of Berlin, HZB, IMTEK (University of Freiburg) and Siemens Energy has developed a highly efficient alkaline membrane electrolyser that approaches the performance of established PEM electrolysers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium. At BESSY II, the team was able to elucidate the catalytic processes in detail using operando measurements, and a theory team (USA, Singapore) provided a consistent molecular description. In Freiburg, prototype cells were built using a new coating process and tested in operation. The results have been published in the prestigious journal Nature Catalysis.