Non-planar A–D–A′–D–A type acceptors enabling EQEs over 5000% in near-infrared organic photomultiplying photodetectors

Abstract

We report two A–D–A′–D–A type non-fullerene acceptors, CS-3 and CS-4, with twisted backbones and low crystallinity. Despite these structural drawbacks, CS-3-based photomultiplying organic photodetectors exhibit an external quantum efficiency (EQE) of 5600% at 800 nm and detectivity exceeding 10¹³ Jones. This work highlights the potential of non-planar molecular designs for achieving high-gain, broadband, near-infrared detection beyond conventional structure–performance expectations.