An asymmetric A-D-π-A type non-fullerene acceptor enables high-detectivity near-infrared organic photodiodes

Narrow bandgap non-fullerene acceptors (NFAs) are relevant as key materials components for the fabrication of near-infrared (NIR) organic solar cells (OSCs) and organic photodiodes (OPDs) thanks to their complementary absorption, tunable energy levels, and enhanced stability. However, high-performance NIR photodetectors are still scarce due to the absence of narrow bandgap NFAs. Herein, an asymmetric A-D-π-A type NFA, named ABTPV-S, with a broad optical absorption approaching 1,000 nm is designed and synthesized through integrating alkylthio side chains and a vinylene π-bridge. The optimal inverted OPD device exhibits an excellent performance with a photoresponsivity of 0.39 A W−1, a noise current of 2.25×10−14 A Hz−0.5, a specific detectivity (D*) of 3.43×1012 Jones at 840 nm, and linear dynamic range (LDR) of 140 dB. In addition, the rise and fall times for ABTPV-S-based OPDs also reach 1.07 and 0.71 µs, respectively. ABTPV-S-based OPDs exhibit a high D over 1012 Jones at 950 nm, which is a competitive result for the self-powered photodiode-type NIR OPDs. These findings highlight the outstanding potential of asymmetric A-D-π-A type NIR NFAs for high-performance OPDs competing with their silicon counterparts.