Tandem perovskite-CIGS solar cells, produced as a result of the collaboration between Lithuanian and German researchers, have reached an efficiency of 23.26 percent, which currently is a world record value in this type of cells. One reason for the success lies in the cell’s intermediate layer of organic molecules: they self-assemble to cover even rough semiconductor surfaces. The self-assembling materials were synthesized at Kaunas University of Technology (KTU), Lithuania.

 

The team of KTU chemists has been studying the use of the self-assembling molecules to form the electrode layer for a couple of years. The material, synthesized at KTU, was applied in the production of a functioning solar cell with just a monolayer-thick selective contact by HZB physicists. They could produce a monolithic tandem solar cell from perovskite and CIGS that achieved an officially certified efficiency of 23.26 percent, which currently is a world record value. The tandem cell has an active area of one square centimeter and thus reaches another milestone, as perovskite CIGS tandem cells have so far been significantly smaller.

 

A new world-record tandem solar cell was presented at EU PVSEC, the world’s largest international photovoltaic and solar energy conference and exhibition, in Marseille, France on September 11, 2019, by Prof Steve Albrecht from the HZB. Two patents have been filed for the layers of the cells.