Approved! The EU INFINITE-CELL project
A large EU-sponsored research project on tandem solar cells in which HZB is participating begins in November 2017. The goal is to combine thin-film semiconductors made of silicon and kesterites into especially cost-effective tandem cells having efficiencies of over 20 per cent. Several large research institutions from Europe, Morocco, the Republic of South Africa, and Belarus will be working on the project, as well as two partners from industry.
“We not only have detailed experience with kesterite thin films, but also a wide spectrum of analytical methods at our disposal to characterise absorber materials very thoroughly”, explains Prof. Susan Schorr. The FUNDACIO INSTITUT DE RECERCA DE L’ENERGIA DE CATALUNYA (IREC), Spain – a long-term collaborating partner of the HZB, is coordinating the entire project. The project begins with a kick-off workshop in Brussels in November 2017.
Ambitious Goals
Goals of the project are quite concrete: the kesterite solar cells should reach an efficiency level of more than 14 per cent (currently they are just below 12%), while thin-film silicon cells made from recycled material should reach an efficiency level of over 16 per cent. Reaching more than 20 % is feasible because silicon uses a different energy region of light to generate electricity than kesterite does. When you combine both materials into one tandem solar cell, where you stack them upon one another or even grow one on the other, it enables a considerably larger proportion of solar energy to be converted into electrical energy. These kinds of especially efficient and also cost-effective solar modules might be employed in cladding, and on roof surfaces – for both buildings and vehicles – to generate power locally.
Why Kesterites?
“Kesterites are a very interesting class of materials”, emphasises Schorr. For even though other absorber materials like copper-indium-gallium-sulphides (CIGS) or metal-organic perovskite semiconductors are able to attain considerably higher efficiency levels today, kesterites trump them with two big advantages: kesterites consist of very abundant elements, and they are non-toxic.
Exchange between partner institutions
The project INFINITECELL, which is a Research and Innovation Staff Exchange (RISE) type funding, has a duration of four years. It is part of the Marie Skłodowska-Curie Actions Programme funded by the EU within Horizon 2020. This enables scientists over the coming years to travel to partner institutions in order to exchange experience, skills, and insights. The joint research is set out in a detailed Secondment Plan.
- Protons against cancer: New research beamline for innovative radiotherapiesTogether with the University of the Bundeswehr Munich, the HZB has set up a new beamline for preclinical research. It will enable experiments on biological samples on innovative radiation therapies with protons.
- 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.
- 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.