Giant molecule acceptors prepared by metal-free catalyzed reactions towards efficient organic solar cells

Abstract

Due to their defined structure and large molecular size, giant molecular acceptors (GMAs) have achieved significant progress in device efficiency and stability for organic solar cells. Unlike the classical synthesis of GMAs by Stille coupling, which still suffers from high cost and lack of environmental sustainability, this work develops three GMAs via metal-free catalyzed reactions. By introducing varying quantities of malononitrile groups into the linker, the optoelectric properties of GMAs can be significantly regulated. A GMA containing only one malononitrile in the central linker unit exhibits a favorable absorption range, energy levels, and molecular packing, consequently achieving high efficiency and stability. Therefore this work provides a feasible approach to developing low-cost and scalable GMAs.