Researchers from HZB and Humboldt University Berlin have developed a CIGS-perovskite tandem solar cell that achieves a record-breaking efficiency of 24.6%, certified by the independent Fraunhofer Institute for Solar Energy Systems.
Researchers from HZB and Humboldt University Berlin have developed a CIGS-perovskite tandem solar cell that has achieved a record-breaking efficiency of 24.6%, as independently certified by the Fraunhofer Institute for Solar Energy Systems.
Tandem solar cells, which combine two semiconductor thin films, offer high efficiency while maintaining a minimal environmental impact. Thin-film solar cells require relatively little energy and material to manufacture, reducing their ecological footprint. While silicon-based solar cells dominate the market, thin-film alternatives such as CIGS (copper, indium, gallium, and selenium) are also widely used. Notably, CIGS thin films can be applied to flexible substrates, expanding their potential applications.
A Breakthrough in Tandem Solar Cell Efficiency
Now, experts from HZB and Humboldt University Berlin, have developed a new tandem solar cell that combines a bottom cell made of CIGS with a top cell based on perovskite. By improving the contact layers between the top and bottom cells, they were able to increase the efficiency to 24.6 %. This is the current world record, as certified by the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany.
As always, this record cell was the result of a successful team effort: the top cell was fabricated by TU Berlin master’s student Thede Mehlhop under the supervision of Stefan Gall. The perovskite absorber layer was produced in the joint laboratory of HZB and Humboldt University of Berlin. The CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. He also used the high-performance cluster system KOALA, which enables the deposition of perovskites and contact layers in a vacuum at HZB.
‘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,’ says Prof. Rutger Schlatmann, spokesman for the Solar Energy Department at HZB.
The record announced is not the first world record at HZB: HZB teams have already achieved world record values for tandem solar cells several times, most recently for silicon-perovskite tandem solar cells, but also with the combination CIGS-perovskite.
We are confident that CIGS-perovskite tandem cells can achieve much higher efficiencies, probably more than 30%,” says Prof. Rutger Schlatmann.
