LAUSR

Abstract Herein, π-extended vinylidenedithiophenmethyleneoxindole (VTI) unit has been incorporated to polymeric conjugated backbones affording two donor-acceptor copolymers such as one-dimensional (1D) copolymer P1 and two-dimensional (2D) copolymer P2. The VTI unit owns S⋯O C intramolecular noncovalent interactions, which is favorable for acquiring planar conjugated backbone, thus leading to enhanced semiconducting properties. Both VTI-based copolymers exhibit broad absorption profiles in the visible region. The highest occupied molecular orbital/the lowest unoccupied molecular orbital energy levels of P1 and P2 are located at −5.21/–3.50 eV, and −5.33/–3.67 eV, respectively. Bulk heterojunction solar cell-based P2 and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) blend afforded an improved power conversion efficiency (PCE) value of 4.75%. These results show that the 2D VTI-based copolymers have greater application prospect than 1D ones, and highlight the great potential of VTI unit as a building blocks for constructing high performance polymer semiconductors for PSCs.