The application of chlorine substituted conjugated block copolymers in the single-component organic solar cells

Abstract

The inferior short-circuit current density (JSC) of the conjugated block copolymers (CBCs) based single component organic solar cells (SCOSCs), compared with that of binary all-polymer systems, is the main reason for their limited power conversion efficiency (PCE). To improve the JSC of SCOSCs by enhancing the light-harvesting ability, we designed and synthesized three narrower bandgap acceptor monomers with different chlorine-substituted terminals, and incorporated them into the CBCs. As the position of chlorine substitution altered, the blend morphology, the device performance, and the physical mechanism changed accordingly. It is worth noting that the PB-b-PYCl-2-based SCOSCs exhibited a significantly improved JSC, accompanied by the best PCE of 13.42 %, and good thermal stability. This study illustrated the terminal chlorination strategy is a promising way to modify the device performance of the SCOSCs.