A novel A-D-A small molecule with 1,8-naphthalimide as a potential non-fullerene acceptor for solution processable solar cells

•The structure-property relationship of fused-ring electron acceptors is briefly discussed.•The principle of molecular design is presented.•A novel non-fullerene acceptor material DNIT-TT2T is designed and synthesized.•OSCs based on P3HT:DNIT-TT2T are investigated, exhibiting high Voc.

In this work, the structure-property relationship of fused-ring electron acceptors is briefly discussed and the principle of molecular design is presented. Based on this principle, perylene diimide (PDI) was cracked by inserting thiophene and thieno[3,2-b]thiophene (TT) to design and synthesize a novel A-D-A (acceptor-donor-acceptor) small molecule DNIT-TT2T, which served as a non-fullerene acceptor material in our fabricated organic solar cells (OSCs). DNIT-TT2T shows excellent thermal stability, it possesses a broad absorption by covering the wavelength range of 300-600 nm and relatively high LUMO energy level of −3.75 eV, which is close to the theoretically calculated value. The power conversion efficiency (PCE) of OSCs based on the blend of P3HT donor and DNIT-TT2T acceptor (1:1, w/w) is found to be 1.25%, with a high open-circuit voltage (Voc) of 0.88 V, indicating that 1,8-naphthalimide (NI) based molecules are promising acceptors for non-fullerene polymer solar cells and excellent photovoltaic properties can be achieved by rationally designing the molecules.

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