Nonfullerene acceptors from thieno[3,2-b]thiophene-fused naphthalene donor core with six-member-ring connection for efficient organic solar cells

Comprehensive design ideas on the fused-ring donor-core in state-of-the-art acceptor-donor-acceptor (A-D-A) nonfullerene acceptors (NFAs) are still of great importance for regulating electron push-pull effect sake optimal light-harvesting, frontier molecular orbital levels, and finally their photovoltaic properties. Herein, thieno[3,2- b ]thiophenes were fused bay-area naphthalene via six-member-ring connection, resulting formation dihydropyrenobisthieno[3,2- ]thiophene based octacyclic ladder-type donor core, which was flanked by two 1,1-dicyanomethylene-3-indanone (IC) acceptor motifs with without 5,6-diflourination, namely PTT-IC PTT-2FIC , respectively, as novel efficient A-D-A (FREAs). Compared fluorinated possesses narrower optical bandgap 1.48 eV, better ?-? stacking, its PBDB-T: blend film exhibited morphology, hole mobility. As a result, solar cells using active layer achieved decent PCE 10.40%, an open-circuit voltage ( V OC ) 0.87 V, fill factor (FF) 0.65, much higher short-circuit current J SC 18.26 mA/cm 2 . Meanwhile, delivered lower 12.58 but 0.99 thus 7.39% due to wider 1.58 eV LUMO energy level. These results demonstrated that NFAs core from fusing connection promising organic applications. • Nonfullerene synthesized. bandgap, intermolecular charge carrier OSCs or PCEs respectively.