Perovskite-silicon solar cell research collaboration hits 25.2% efficiency
Perovskite-based tandem solar cells can achieve now efficiencies better than 25%. © HZB
A 1 cm2 perovskite silicon tandem solar cell achieves an independently certified efficiency of 25.2 %. This was presented this week at an international conference in Hawaii, USA. The cell was developed jointly by HZB, Oxford University and Oxford PV - The Perovskite CompanyTM.
"Perovskite-based tandem solar cells can use light particularly efficiently and therefore offer the opportunity to achieve even higher efficiencies. That is why we have significantly expanded our expertise with the new Helmholtz innovation laboratory HySPRINT," says Prof. Dr. Rutger Schlatmann, Director of the Competence Center Thin Film and Nanotechnology for Photovoltaics Berlin (PVcomB) at HZB. "In our cooperation with Oxford PV, we aim to further optimize perovskite silicon tandem cells, demonstrate their scalability and facilitate their integration into large-area solar modules. For this new result we have optimized our high-efficiency silicon heterojunction bottom cell and developed an optical adaptation to the top cell using a very specific SiOx intermediate layer".
At the World Conference on Photovoltaic Energy Conversion, WCPEC-7 in Waikoloa, Hawaii, tandem solar cells involving perovskites were an important topic: two records have been presented with 25.2% certified efficiency: one from the group of Prof. Christophe Ballif at EPFL/CSEM and one from the consortium HZB/OxfordPV/Oxford University, presented by HZB scientist Dr. Bernd Stannowski. The third one, with 25.0% certified efficiency is a tandem cell developed by an HZB team headed by Dr. Steve Albrecht.
Oxford PV was established in 2010 and has had a close working relationship with Professor Snaith’s research group at the University of Oxford. In January 2018, Oxford PV announced its collaboration with HZB, the leading German research centre focused on energy materials research.
Press Release by Oxford PV
More Information on PVcomB at HZB
More Information on HySPRINT at HZB
More Information on the group Photovoltaics and Optoelectronics at University of Oxford
- New method shows how molecular switches are influenced by their neighborsResearchers at Friedrich Schiller University Jena and the Helmholtz Centre Berlin (HZB) have, for the first time, been able to directly observe how the environment surrounding a molecular switch influences its electronic structure. Molecular switches are molecules that can be switched between two states by external influences such as changes in temperature—similar to a switch with the positions »On« and »Off«. Such molecules are being investigated as potential building blocks for future data storage devices or sensor materials. Using magnetic-field-dependent terahertz spectroscopy, the researchers have now, for the first time, been able to distinguish whether neighbouring molecules in a material are in the same or different states. The results have been published in the journal »Angewandte Chemie International Edition«.
- 3D magnetic field experiment at BESSY II takes spintronics a step further(Fe0.63Ni0.3Pd0.07)3P or FNPP is a magnetic material that exhibits complex magnetic structures even at room temperature. This makes the material of interest for spintronics, a field that could enable data processing with significantly lower energy consumption. One potential application is novel magnetic memory devices. However, generating and modifying the desired structures in a controlled manner remains a challenge to date. A new study led by HZB has now taken a step forward in this regard. They demonstrated at the worldwide unique VEKMAG-Station at BESSY II, that a tiny external B-field in the plane of the magnetic patterns is sufficient to change them.
- BESSY II: Evaporated perovskites in tandem solar cells improvedPerovskite-silicon tandem solar cells achieve significantly higher efficiencies than silicon solar cells on their own. One particularly attractive method is co-evaporation of the perovskite precursor molecules on top of the silicon subcell. Scientists at HZB have analysed film growth on the nanoscale at BESSY II and found a new way to improve the quality of the perovskite layer: adding a thin seed layer of caesium chloride between the two sub-cells promotes uniform perovskite growth and suppresses the formation of undesired lead iodide at the interface.