Combining two thin semiconductor films into a tandem solar cell can lead to high efficiency with a reduced environmental impact. Recently, researchers unveiled a new CIGS-perovskite tandem cell that has achieved an impressive efficiency of 24.6%, a record verified by an independent organization.
By merging two semiconductor thin films into one tandem solar cell, remarkable efficiencies can be attained while ensuring a low environmental impact. Recently, teams from HZB and Humboldt University Berlin unveiled a CIGS-perovskite tandem cell that has set a new benchmark, boasting an efficiency of 24.6%, certified by the independent Fraunhofer Institute for Solar Energy Systems.
Thin-film solar cells are known for their low energy and material requirements during production, resulting in a considerably small environmental footprint. In addition to the widely recognized silicon solar cells, there are also thin-film variants, such as CIGS cells that utilize copper, indium, gallium, and selenium. Notably, CIGS thin films can be applied to flexible materials.
Recently, specialists from HZB and Humboldt University Berlin developed an advanced tandem solar cell that integrates a CIGS bottom cell with a perovskite top cell. By refining the contact layers between these two cells, they enhanced the efficiency to an impressive 24.6%. This achievement has been certified as the highest efficiency to date by the Fraunhofer Institute for Solar Energy Systems ISE, located in Freiburg, Germany.
The development of this record-setting cell was the result of collaborative effort: the top cell was created by TU Berlin master’s student Thede Mehlhop under the guidance of Stefan Gall. The perovskite absorber layer was produced in a joint laboratory run by HZB and Humboldt University of Berlin. The CIGS sub-cell and the contact layers were crafted by HZB researcher Guillermo Farias Basulto, who utilized the high-performance KOALA cluster system for vacuum deposition of the perovskites and contact layers at HZB.
‘At HZB, we have expert laboratories and highly skilled professionals who excel in their specialties. This world record tandem cell is a testament to their successful collaboration,’ remarks Prof. Rutger Schlatmann, spokesperson for the Solar Energy Department at HZB.
This newly set record marks not the first milestone for HZB; the teams at HZB have previously achieved world record efficiencies for tandem solar cells, including combinations of silicon-perovskite and CIGS-perovskite.
‘We believe that CIGS-perovskite tandem cells have the potential to exceed even higher efficiencies, likely surpassing 30%,’ states Prof. Rutger Schlatmann.
