HZB sets new efficiency record for CIGS perovskite tandem solar cells

HZB sets new efficiency record for CIGS perovskite tandem solar cells

by Robert Schreiber

Berlin, Germany (SPX) Feb 05, 2025

Researchers at Helmholtz Center Berlin for Materials and Energy (HZB) and Humboldt University Berlin have developed a CIGS-perovskite tandem solar cell that has set a new world record for efficiency, achieving 24.6%. The performance of the cell has been officially certified by the Fraunhofer Institute for Solar Energy Systems.

Thin-film solar cells, such as those based on copper, indium, gallium, and selenium (CIGS), require minimal material and energy to manufacture, making them an environmentally friendly alternative to conventional silicon-based solar cells. CIGS thin films can also be applied to flexible substrates, expanding their potential applications.

The new tandem solar cell developed by HZB and Humboldt University combines a CIGS bottom cell with a perovskite top cell. By optimizing the contact layers between these two components, the research team successfully increased efficiency to a record-breaking 24.6%. This milestone was confirmed by the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany.

This achievement was made possible through a collaborative effort among researchers. The top cell was developed by Thede Mehlhop, a master’s student at TU Berlin, under the supervision of Stefan Gall. The perovskite absorber layer was created in the joint laboratory of HZB and Humboldt University Berlin, while the CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. Additionally, the KOALA high-performance cluster system at HZB was used to deposit the perovskite and contact layers in a vacuum.

“At HZB, we have highly specialized laboratories and experts who are top performers in their fields. With this world record tandem cell, they have once again shown how fruitfully they work together,” said Prof. Rutger Schlatmann, spokesman for the Solar Energy Department at HZB.

HZB has a strong track record in achieving world records in solar cell efficiency, including past accomplishments in silicon-perovskite tandem cells and now in CIGS-perovskite tandem technology.

“We are confident that CIGS-perovskite tandem cells can achieve much higher efficiencies, probably more than 30%,” said Prof. Rutger Schlatmann.