Nonfused-Core-Small-Molecule-Acceptor-Based Polymer Acceptors for All-Polymer Solar Cells

Polymerizing the narrow bandgap small-molecule architecture with a conjugated linking unit (or called the polymerized small molecule acceptors (PSMAs)) is a promising strategy to design polymer acceptors for efficient all polymer solar cells (all-PSCs). Currently, the fused-ring-based small molecule acceptors (SMAs) are preferred monomers to design efficient PSMAs, leaving the challenge of reducing the materials cost. In this work, we firstly employ nonfused-core SMA with simple synthetic procedures to design PSMAs (namely PBTI-H, PBTI-F and PBTI-Cl) to address this issue. Relative to the fused-ring based counterparts, these three PSMAs exhibit much higher figure-of-merit value. Additionally, a power-conversion efficiency of 8.80% is achieved in the PBTI-Cl-based all-PSC. The results offer an attractive approach to design low-cost PSMAs for efficient all-PSCs.