A new world-record-setting photovoltaic cell developed by HZB combines the semiconductors perovskite and CIGS to a monolithic ‘two-terminal’ tandem cell. Due to the skinny-film technologies used, such tandem cells survive much longer in space and may even be produced on flexible films.
The brand new tandem cell achieves a certified efficiency of 24.16%.
Tandem cells mix two semiconductors that convert different components of the light spectrum into electrical energy. Steel-halide perovskite compounds primarily use the visible elements of the spectrum, while CIGS semiconductors convert infrared light.
CIGS cells, which consist of copper, indium, gallium, and selenium, can be deposited as thin films with a total thickness of 3 to 4 micrometers; the perovskite layers are a lot thinner, at 0.5 micrometers. The new tandem photovoltaic cell fabricated from CIGS and perovskite thus has a thickness of well below 5 micrometers, which would permit the production of flexible solar modules.
Albrecht and his staff have deposited within the HySPRINT lab at HZB the perovskite layer instantly on the rough CIGS layer. “We used a trick that we had previously developed,” explains former postdoc from Albrecht’s group Dr. Marko Jošt, who’s now a scientist at the University of Ljubjana, Slovenia.
They employed so-called SAM molecules to the CIGS layer, which form a self-organized monomolecular layer, improving the contact between perovskite and CIGS.