Helmholtz Association promotes HZB cooperation with Slovenia on perovskite silicon tandem solar cells
Marko Jošt was a PhD student in the HySPRINT-Lab in Steve Albrecht's group. Now he will continue his research on tandem solar cells at the university of Lubljana. © M. Setzpfandt/ HZB
A HZB team has successfully raised funds from the “Helmholtz European Partnering Program” of the Helmholtz Association to expand cooperation with partners of the University of Ljubljana, Slovenia. The topics of the cooperation are tandem solar cells made of perovskite and silicon and, in particular, their precise characterisation.
Currently, most solar modules consist of silicon, a semiconductor that mainly uses the red parts of the solar spectrum to generate electricity. The combination of silicon with perovskite semiconductors therefore promises great opportunities for even higher efficiencies. Semiconductor materials from this material class convert the energy-rich, blue parts of the spectrum into electricity.
Now the HZB physicist Prof. Dr. Steve Albrecht has raised funds from the Helmholtz Association to investigate such tandem solar cells with partners from the University of Ljubljana, Slovenia. The TAPAS project is funded by the Helmholtz European Partnering programme for the next three years with 250,000 euros per year each. Following an evaluation, the funding period can be extended by two years. The Helmholtz European Partnering programme was set up to strengthen the European research area, in particular cooperation with countries in Southern, Central and Eastern Europe.
The name TAPAS stands for "Tandem Perovskite and Silicon solar cells - Advanced opto-electrical characterization, modeling and stability". Together with opto-electrical modelling, highly efficient and stable next-generation tandem solar cells are to be developed for the energy system of the future.
The Working Group for Photovoltaics and Optoelectronics at the University of Ljubljana (LPVO, headed by Prof. Dr Marko Topič) and the Helmholtz-Zentrum Berlin have established a very successful cooperation in recent years, which will be further strengthened by this funding. The aim of the cooperation is to analyse the processes that affect the stability of the modules in the field.
- CIGS-perovskite tandem cell achieves record efficiency of 25.5 %A Berlin-based team from HZB and Center for the Science of Materials Berlin (CSMB) at the Humboldt-Universität zu Berlin has set a new record for a tandem solar cell. Using a combination of a CIGS semiconductor layer and perovskite, along with several optimised intermediate layers, they were able to convert 25.5% of sunlight into electrical energy. The previous record for this combination of materials and this size of cell stood at 24.6%. The new record has been certified and is visible in the prestigious Solar Cell Efficiency Tables (the "Green Tables"), which serve as the definitive ledger for the global photovoltaic community.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Perovskite solar cells: Predictions of long-term stabilityReliable statements about the long-term stability of perovskite solar cells are still difficult to make. However, a new study by Dr Carolin Ulbrich’s team, published in the renowned journal Joule, highlights which methods are useful for this purpose and identifies areas where further research is needed.