A novel small molecular electron donor with an optimized side group was synthesized for solution-processed organic solar cells. In order to extend the conjugation length in 2-dimensional structure, 5-alkylthio-thieno[3,2-b]thiophene was attached onto the central benzo[1,2-b:4,5-b’]dithiophene unit. The small molecule exhibited an optical energy gap of 1.71 eV, low-lying energy levels, strong intermolecular interaction in solid state, which result in promising power conversion efficiency up to 7.15% with ITIC as a non-fullerene electron acceptor. This work demonstrates the potential of optimal side chain of small molecular donor for high performance of solution-processed non-fullerene organic solar cells.

合成了具有优化侧基的新型小分子电子供体，用于溶液处理的有机太阳能电池。为了延长二维结构中的缀合长度，将5-烷硫基-噻吩并[3，2- b ]噻吩连接到中央苯并[1,2- b：4,5- b ']二噻吩单元上。这个小分子表现出1.71 eV的光能隙，低能级，固态的分子间相互作用，在ITIC作为非富勒烯电子受体的情况下，有望实现高达7.15％的功率转换效率。这项工作证明了小分子供体的最佳侧链对于溶液加工的非富勒烯有机太阳能电池高性能的潜力。