Utilizing Benzotriazole-Fused DAD-Type Heptacyclic Ring to Construct n-Type Polymer for All-Polymer Solar Cell Application
Baoquan Zhang, Jianfeng Li, Ailing Tang, Yanfang Geng, Qiang Guo, Erjun Zhou
Abstract
Polymerizing small-molecule acceptor is a valid method for combining the advantages of small molecule acceptors and polymer acceptors. Here, a weak electron-deficient unit, benzo[d][1,2,3]-triazole (BTA) was fused to get the heptacyclic ring of dithienothiophen[3,2-b]-pyrrolobenzo[d][1,2,3]-triazole (TPBTA), which was utilized as DAD unit to synthesize a A′-DAD-A′-D′ type polymer acceptor (named as A702). After being blended with classic p-type polymer PBDB-T, a high PCE of 11.84% with an open-circuit voltage (VOC) of 0.9 V was achieved. Our results indicate the heptacyclic ring containing BTA unit can be regarded as an attractive option to build high-efficient PAs.