A lactam building block for efficient polymer solar cells

Abstract

A new lactam acceptor unit, [7,7′-bidithieno[3,2-b:2′,3′-d]pyridine]-5,5′(4H,4′H)-dione (BDTP), was developed. A D–A copolymer PThBDTP using BDTP as the acceptor unit and thiophene as the donor unit was synthesized. PThBDTP:PC₇₁BM solar cells gave a decent PCE of 9.13% with a V_oc of 0.96 V. PThBDTP is one of the few D–A copolymers with PCEs of over 9%.