Enhanced photovoltaic performance of organic solar cells with low cost azomethine-based non-fullerene acceptors

Most of non-fullerene acceptors used in organic solar cells are synthesized through cross-coupling reactions, which require expensive transition metal catalysts, harsh reaction conditions and complex purification processes, making large-scale production high cost. Here, two azomethine-based perylene diimides (PDIs) are designed and synthesized through a simple and economical Schiff base condensation reaction with water as the only by-product. As the non-fullerene acceptors for organic solar cells, power conversion efficiencies exceeding 4.3 % were reached. Furthermore, the cost estimations show that the material cost of azomethine-based PDIs is about two orders of magnitude lower. In addition, the synthesis of azomethine-based PDIs also reduces the toxic chemical waste, thus greatly reducing the environmental impact. Our results pave the way for low-cost, environmentally friendly and efficient non-fullerene acceptors.