A record year for our living lab for building-integrated PV
© BAIP/HZB
In 2025, our solar facade in Berlin-Adlershof generated more electricity than in any of the previous four years of operation.
With about 32 MWh, the solar facade of our BIPV living laboratory produced enough electricity to power more than 12 average four-person households. Thanks to the energy-intensive research landscape at the Helmholtz-Zentrum Berlin, we can also consume all of the electricity generated on site at any time.
Even after five years of operation, our building-integrated solar modules show no measurable degradation. Differences in annual energy yield can so far be attributed exclusively to weather-related fluctuations. According to the German Weather Service, the duration of sunshine in 2025 was around 1,900 hours nationwide. In addition, the year was comparatively low in precipitation, which, together with the high duration of sunshine, explains the high solar yield.
However, we were particularly surprised by December: exceptionally good PV weather led to yields more than twice as high as in the previous year! Especially in spring, autumn and winter, the sun is more favourable for the solar facade, so we regularly observe higher yield peaks than in the summer months.
We are excited to see how this year will turn out.
- BESSY II: New sample environment allows glimpse into thermocatalytic processesA novel measurement cell allows, for the first time, soft and hard X-ray investigations under high pressures of up to 20 bar and temperatures of up to 400°C. This provides new insights into thermocatalytic processes, such as the Fischer-Tropsch synthesis for producing synthetic fuels. The development of the measurement cell is considered a significant achievement within the Care-O-Sene project.
- Precision interface chemistry pushes perovskite solar cells beyond 26% efficiencyAn international research collaboration has developed a new molecular strategy for controlling one of the most critical interfaces in perovskite solar cells. The resulting solar cells reached a power conversion efficiency of 26.19% in the n i p architecture, together with strong operational stability under prolonged illumination and elevated temperature. The results have been published in the Journal of the American Chemical Society.
- Perovskite triple-junction solar cells: Even more efficient with GO/SAM bilayersPerovskite semiconductors efficiently convert sunlight into electrical energy; they are also inexpensive and extremely lightweight. A team at HZB has developed a triple-junction solar cell comprising different perovskite semiconductors, with a novel bilayer of graphene oxide (GO) and a self-assembled monolayer (SAM) as the hole conductor. This bilayer significantly increases both efficiency and long-term stability. The efficiency of the novel perovskite triple-junction solar cell is 27.3% and shows hardly any decline even after more than 770 hours of operation. The study has been published in the renowned journal Joule.