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.
- 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.
- Peat as a sustainable precursor for fuel cell catalyst materialsIron-nitrogen-carbon catalysts have the potential to replace the more expensive platinum catalysts currently used in fuel cells. This is shown by a study conducted by researchers from the Helmholtz-Zentrum Berlin (HZB), Physikalisch-Technische Bundesanstalt (PTB) and universities in Tartu and Tallinn, Estonia. At BESSY II, the team observed the formation of complex microstructures within various samples. They then analysed which structural parameters were particularly important for fostering the preferred electrochemical reactions. The raw material for such catalysts is well decomposed peat.
- Helmholtz Investigator Group on magnonsDr Hebatalla Elnaggar is setting up a new Helmholtz Investigator Group at HZB. At BESSY II, the materials scientist will investigate so-called magnons in magnetic perovskite thin films. The aim is to lay the foundations for future terahertz magnon technology: magnonic devices operating in the terahertz range could process data using a fraction of the energy required by the most advanced semiconductor devices, and at speeds up to a thousand times faster.