Dinaphtho-s-indacene-based copolymers for inverted organic solar cells with high open-circuit voltages

A series of dinaphtho-s-indacene based donor-acceptor copolymers (PF1, PF2, PF3 and PF4) with deep-lying HOMO energy levels were synthesized, and they were used as donor materials to fabricate inverted solar cells. The solar cells based on PF1 show a PCE of 3.07%, with a high Voc of 0.99 V.