Synthesis of a new wide-bandgap conjugated copolymer with 3-trifluoromethylthiophene monomer and Its application to non-fullerene polymer solar cells

Abstract

In this study, a novel wide-bandgap conjugate donor-acceptor type copolymer, PBDT-TFMTh, containing benzodithiophene (BDT) as a donor unit and trifluoromethyl (TFM)-substituted thiophene (Th) as an acceptor unit was designed and synthesized. The physical, optical, and electrochemical properties of PBDT-TFMTh were studied in detail and it was found to have lower-lying highest occupied and lowest unoccupied molecular orbitals. The polymer solar cell with an active layer consisting of PBDT-TFMTh and acceptor IDT(TCV)(2) showed a relatively high power conversion efficiency of 2.25% after thermal annealing at 120??C.