Application of indacenodiselenophene central core and modulation of terminal group interaction for high-efficient P3HT-based organic solar cells

As one of the cheapest photovoltaic polymers, poly(3-hexylthiophene) (P3HT) has been considered as one of the prospective donor materials for commercial application. Thus, various non-fullerene acceptors (NFAs), especially A 2 -A 1 -D-A 1 -A 2 type molecules comprising one electron-donating (D) unit and two electron-withdrawing (A) units have been designed to improve the photovoltaic performance of P3HT. So far, the central D unit has been dominated by large conjugated heterocycles fused with thiophene and benzene rings. Herein, indacenodiselenophene (IDSe) and benzo[ d ][1,2,3]triazole (BTA) were utilized as the central D part and bridged A 1 unit respectively, to synthesize two novel A 2 -A 1 -D-A 1 -A 2 type NFAs BTA46 and BTA47 . To modulate the molecular planarity, absorption spectra and energy levels, 3-benzyl-rhodanine ( R-Bn ) and 3-benzyl-2-(1,1-dicyanomethylene)rhodanine ( RCN-Bn ) were used as the terminal units. P3HT: BTA47 combination demonstrates a higher PCE of 7.12% benefiting from the more efficient charge generation and transport in comparison with P3HT: BTA46 blend, which exhibits an inferior PCE of 3.99%. Detailed photoelectric properties and charge generation process analysis indicate that IDSe is a promising central core for A 2 -A 1 -D-A 1 -A 2 type NFAs to combine with P3HT. Two IDSe-based A 2 -A 1 -D-A 1 -A 2 type acceptors BTA46 and BTA47 were synthesized and used in P3HT devices for the first time. The BTA47 -based device achieved high PCE of 7.12%, due to excellent exciton dissociation, charge transport and collection.