Asymmetric fluorine and chlorine side-chain engineered quinoxaline-based D–A copolymer for both fullerene and nonfullerene polymer solar cells

A novel copolymer donor (Qx) based quinoxaline with asymmetric side chains, namely PBDTTS-2FClQx, is synthesized. The PCE of optimized ternary OSC (PBDTTS-2FClQx:Y6:PC 71 BM = 1 : 0.9 : 0.1) is 13.59%, but binary PBDTTS-2FClQx:Y6 (12.41%).