US Patent 11189663 Efficient interconnecting layer for tandem solar cells

A tandem solar cell comprises a front subcell; a back subcell; and an interconnecting layer of Cr/MoO3 between the front subcell and the back subcell and connecting the two subcells in series. The back subcell may be an isoindigo-based polymer. The front subcell may comprise a carbazole-thienyl-benzothiadiazole based polymer. The front subcell may comprise an isoindigo-based polymer. The isoindigo-based polymer is a repeating 2-thiophene-terminated polymer. A tandem solar cell comprises a substrate layer; a layer of PCDTBT:PC71BM applied on the substrate layer; a bilayer of chromium and MoO3 applied to the PCDTBT:PC71BM layer; a layer of P(T3-il)-2:PC71BM applied on the bilayer of chromium and MoO3; and Ca and Al electrode layer on the top.