Near-infrared (NIR) electron acceptors are critical components
for constructing organic solar cells (OSCs). Herein, we report a set
of A-DA′D-A-type electron acceptors with end-groups of cyano-substituted
2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile
(CN-IC), which possesses the strongest electron-withdrawing ability
among the end-groups reported to date. An optical bandgap as low as
1.29 eV was obtained for the electron acceptors with CN-IC end-groups,
which is decreased by 0.12 eV with respect to that of the reference
electron acceptor. Meanwhile, deep-lying frontier molecular orbital
energy levels were maintained in these electron acceptors. These advantages
endow the electron acceptors with a broad light-harvesting range and
the capacity to match prevalent polymer donors. Consequently, OSCs
with a power conversion efficiency of 18.1% were obtained. These results
suggest the huge potential of CN-IC in constructing NIR electron acceptors.