• Prathapani, S.; Lauche, J.; Klenk, R.; Kaufmann, C.A.; Lauermann, I.: Ag-alloyed wide bandgap chalcopyrite solar cells with Zn(O,S) buffer layers. In: 34th International Photovoltaic Science and Engineering Conference (PVSEC-34) : Shenzen, China, Nov. 6-10, 2023Shenzen, 2023, p. 802-804

A tandem solar cell configuration needs a high-efficiency wide bandgap solar cell as a top cell joined with a low band gap bottom cell of, e.g. Cu(In,Ga)Se2 or cystalline-Si. In view of long-term stability and industrial adaptability for commercialization, we explore wide bandgap Cu(In,Ga)Se2 thin film absorbers for top cell applications. We present here results on the fabrication of Cu(In,Ga)Se2-based wide band gap semiconductor thin films with Ag alloying suitable for use as absorber layers in top cells. A small fraction of Ag alloying significantly improves the absorber quality, yielding better charge collection. So far, our (Ag, Cu)(In,Ga)Se2 wide bandgap solar cells with Zn(O,S) buffer layers as an alternative to CdS yield a best photoconversion efficiency of 7.7%.