An efficient PDPPTPT:PC61BM-based tandem polymer solar cells with a Ca/Ag/MoO3 intermediate layer

We report an efficient tandem polymer solar cell (PSC), consisting of two active layers of poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PC61BM) and poly[{2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl} -alt-{[2,2′-(1,4-phenylene)bisthiophene]-5,5′-diyl}]:PC61BM. The two active layers are connected by a Ca (1 nm)/Ag (1 nm)/MoO3 (10 nm) intermediate layer, which is superior to a Ca (1 nm)/Al (1 nm)/MoO3 (10 nm) intermediate layer for better performance. The tandem PSC with complementary spectral absorption from 300 to 850 nm showed a power conversion efficiency of 4.50% under AM1.5G, 100 mW cm−2 illumination and an efficiency improvement of about 25.0% over the single-stack sub-cells.