Poster award for HZB PhD student
John Uhlrich, Editor-in-Chief at Wiley VCH presented an award to Quentin Jeangros, EPFL, and Eike Köhnen, HZB, for their outstanding posters (from left to right). © Gruppe Steve Albrecht/HZB
Eike Köhnen received an award for his poster on perovskite silicon tandem cells at the 4th International Conference on Perovskite Solar Cells and Optoelectronics (PSCO) in Lausanne, Switzerland. He is a PhD student in the Junior Research Group on Perovskite Tandem Cells led by Dr. Steve Albrecht.
Tandem cells made of organometallic perovskite layers and silicon have the potential for very high efficiencies. While perovskites in particular convert blue parts of the light spectrum into electrical energy, silicon uses the red parts of the light. Eike Köhnen is working on the design of a so-called monolithic tandem cell.
For his poster, which he presented at the 4th International Conference on Perovskite Solar Cells and Optoelectronics (PSCO) in Lausanne, Switzerland, he received an award sponsored by Wiley Science Publishers.
Köhnen has realized a highly efficient monolithic tandem solar cell with an efficiency of 25 percent, which has also been certified by independent bodies. The tandem cell was manufactured at HZB, the silicon cell being produced at HZB-Institute PVcomB and the perovskite cell at HySPRINT. By optimizing the optical and electrical properties of the tandem-top contact, it was even possible to achieve an efficiency of 26 percent, which is the highest efficiency currently published in the literature for this tandem architecture. Since the spectrum arriving on Earth changes over the course of the day, Köhnen also investigated the influence of the spectrum on the behavior of the tandem solar cell.
- Bright prospects for tin perovskite solar cellsPerovskite solar cells are widely regarded as the next generation photovoltaic technology. However, they are not yet stable enough in the long term for widespread commercial use. One reason for this is migrating ions, which cause degradation of the semiconducting material over time. A team from HZB and the University of Potsdam has now investigated the ion density in four different, widely used perovskite compounds and discovered significant differences. Tin perovskite semiconductors produced with an alternative solvent had a particular low ion density — only one tenth that of lead perovskite semiconductors. This suggests that tin-based perovskites could be used to make solar cells that are not only really environmentally friendly but also very stable.
- Joint Kyiv Energy and Climate Lab goes liveHelmholtz-Zentrum Berlin and the National University of Kyiv-Mohyla Academy established on 27 November a Joint Energy and Climate Lab.
- How carbonates influence CO2-to-fuel conversionResearchers from the Helmholtz Zentrum Berlin (HZB) and the Fritz Haber Institute of the Max Planck Society (FHI) have uncovered how carbonate molecules affect the conversion of CO2 into valuable fuels on gold electrocatalysts. Their findings reveal key molecular mechanisms in CO2 electrocatalysis and hydrogen evolution, pointing to new strategies for improving energy efficiency and reaction selectivity.