High-performance asymmetric small molecular donor materials based on indenothiophene for solution-processed organic solar cells

摘要

Two novel asymmetric organic small molecules of IT(2FBT-T3Cz)2 and IT(2FBT-TT3Cz)2 with an indenothiophene (IT) central donor core,fluorinated benzothiadiazole (2FBT) as acceptor and 3-carbazole (Cz) unit as terminal group were designed and synthesized as the donor materials in organic solar cells (OSCs).The thermal,optical absorption,electrochemical property,hole-electron mobility,film morphology were thoroughly studied.Using PC71BM as an electron acceptor,without any additive and thermal annealing (TA) treatment,the IT(2FBT-T3Cz)2-based cells showed a promising power conversion efficiency (PCE) of 5.81% and the IT(2FBT-TT3Cz)2-based cells exhibited a PCE of 4.39%.Our results demonstrate that the IT-based asymmetric small molecules can be developed as a promising class of donor materials for highperformance OSCs.