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Researchers at the Fraunhofer Institute for Solar Energy Systems ISE have succeeded in developing solar cells based on III-V semiconductors that can achieve an efficiency of over 40 percent indoors. By the optimized design and improved quality of the solar cell absorber material , the research team achieved remarkably high efficiencies even under very low light conditions of just 100 lux. This result makes this technology particularly attractive for autonomous Internet of Things (IoT) applications that operate indoors without an external wired power supply. The findings were published in the journal Applied Physics Letters.

In a joint research effort, scientists from King Abdullah University of Science and Technology KAUST and Fraunhofer Institute for Solar Energy Systems successfully replaced spin-coating with blade-coating in the production of perovskite-silicon tandem solar cells. In a “hybrid route” combining evaporation and blade-coating to deposit perovskite solar cells on silicon bottom cells, they produced tandem solar cells with efficiencies approaching 28 percent. Their result opens a path to the large-scale production of this promising new solar cell technology.

Together with the company III/V-Reclaim, scientists at the Fraunhofer Institute for Solar Energy Systems ISE have succeeded in producing high-quality indium phosphide on gallium arsenide substrates (InP-on-GaAs wafers) with up to 150 mm diameter. These new wafers can effectively replace classic indium phosphide in a variety of applications, offering a scalable pathway to lower cost. The research team developed a process to deposit a thin layer of high-quality InP on GaAs. Following a special surface treatment, these wafers are delivered epi-ready, enabling customers to directly grow III-V epitaxial structures and manufacture high-performance InP-based semiconductor devices.

Without a significant reduction in silver content, the global demand for photovoltaics to ensure a sustainable, climate-neutral energy system cannot be met. Scientists at the Fraunhofer Institute for Solar Energy Systems ISE have now produced silicon heterojunction solar cells (SHJ) with a total silver consumption of just 1.4 milligrams per watt peak. This is about one tenth of the current standard in industrial production. To achieve this, they strongly reduced the silver content in the metallization paste for the front side metallization and completely replaced silver with copper paste on the rear side. An optimized printing process also ensured very fine electrical contacts. The copper-metallized SHJ solar cells even achieved a higher efficiency than their reference cells with traditional silver contacts.

The Fraunhofer Institute for Solar Energy Systems ISE has been conducting world-leading research on highly efficient III-V multi-junction solar cells for over 20 years. To further develop this promising next generation PV technology and lead it to economic success, the institute is now receiving prominent support: The Werner Siemens Foundation will fund the project "Sustainable Energy Transition through High Efficiency Tandem Photovoltaics" with 14 million euros until 2032.

On April 3, 2025, Fraunhofer Chile celebrated the 10th anniversary of its Center for Solar Energy Technologies (CSET) with a festive event. The research center supports the development of a sustainable solar economy and the energy transition in Chile. The Fraunhofer Institute for Solar Energy Systems ISE was the initiator of the CSET's establishment and has closely cooperated with Chilean partners in various research fields since its inception.

Can photovoltaics on rewetted peatlands reduce land-use conflicts in Germany and make rewetting more attractive for the agricultural sector? Researchers from the Universities of Greifswald and Hohenheim, together with the Johann Heinrich von Thünen Institute and the Fraunhofer Institute for Solar Energy Systems ISE, want to answer this question. The ‘MoorPower’ project aims to investigate the general feasibility of photovoltaic systems on peatland areas that will be rewetted at the same time. The Federal Ministry of Education and Research (BMBF) is providing a grant sum of seven million euros for a period of three and a half years.

The Fraunhofer Institute for Solar Energy Systems ISE and the University of Auckland in New Zealand have signed an agreement to collaborate on AI-based data analysis. The two research institutes want to establish a long-term cooperation that brings together their complementary expertise. Important fields of application are the quality assurance of battery cells and intelligent battery production. Initial exchanges and the joint supervision of students have already begun.

The 5th International Conference on Electrolysis ICE 2025 will be held in Freiburg, Germany, from August 25 to 29, 2025. This event provides a key platform for technical experts in industry, academic researchers and PhD students, for example, to share breakthroughs in water electrolysis, particularly in its role as a technology for green hydrogen production. The organizing committee has already launched the Call for Papers, which remains open until end of January 2025.

Dr. Jasna Jankovic, Associate Professor at the Institute of Materials Science and Engineering at the University of Connecticut, has been awarded the Fraunhofer Bessel Research Award by the Alexander von Humboldt Foundation. She was nominated for the award by the Fraunhofer Institute for Solar Energy Systems ISE, where she will be working as a visiting scientist from December 1. The focus of the joint research work is the development of advanced ex-situ characterization methods for state-of-the-art, innovative fuel cell and electrolyser materials.