LAUSR

Abstract Two new small-molecule nonfullerene acceptors containing methyl- and fluorine-substituted 2-(2,3-dihydro-3-oxo-1H-inden-1-ylidene)propanedinitrile (INCN) as end groups, namely, NFBDT-Me and NFBDT-F, were designed, synthesized and applied in organic solar cells. The influence of the methyl and fluorine groups on the absorption ability, energy levels, and photovoltaic performances was fully investigated. Compared to their parent molecule NFBDT, these two nonfullerene acceptors based devices exhibit higher PCEs with values of 11.00% and 10.62%, respectively. For NFBDT-Me, the improvement of PCE is mainly attributed to the higher Voc, while for NFBDT-F, the increase of Jsc promotes the higher PCE. This suggests that appropriate manipulation of the end-group substituents of these non-fullerene acceptors is a promising way to enhance the PCEs of non-fullerene based OSCs.