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.
- 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.
- Hatice Mutlu appointed to the Helmholtz Institute HIPOLE in JenaProf. Dr Hatice Mutlu is the new professor of sustainable polymer chemistry at HIPOLE Jena, the Helmholtz Institute for Polymers in Energy Applications. On 17 August 2026, she visited the HZB campus in Berlin-Adlershof including the BESSY II lightsource and discussed future collaboration with researchers and the board of directors.