Noncovalent Conformational Locks Enabling Efficient Nonfullerene Acceptors
María Privado, Anupam Agrawal, Pilar de la Cruz, M. L. Keshtov, Ganesh D. Sharma, Fernando Langa
Abstract
A simple synthesis of highly planar extended π ‐electron molecules is of particular interest for the development of efficient nonfullerene acceptors in organic solar cells with high light absorption and high mobility. Herein, two small‐molecule acceptors ( MPU7 and MPU8 ) with a diketopyrrolopyrrole core connected to CPTCN end‐capping groups (A 2 ) via thienylethynylselenophene ( MPU7 ) or thienylethynylthiophene ( MPU8 ) linkers are conceived and synthesized. Planarity of the conjugated skeleton is achieved in both molecules, thanks to the existence of four (Se⋯O or S⋯O) noncovalent, through‐space intramolecular interactions. Both nonfullerene small‐molecule acceptors show broad absorption in the visible and near‐infrared region (up to 930 nm). As a result, the binary solar cells constructed together with a polymer donor (P) display power conversion efficiencies as high as 14.12%. Devices built with MPU7 (containing the selenophene) show better film morphology, electron mobility, and higher efficiency than those containing thiophene ( MPU8 ).