Suppressing Dark Current in Near-Infrared Organic Photodetectors by Employing a Donor–Insulator–Acceptor Architecture

Abstract Near-infrared organic photodetectors (NIR OPDs) have great potential for sensing and imaging systems. However, the high dark current level remains a major obstacle to achieving high sensitivity and weak light detection for NIR OPDs. Herein, we propose a strategy for dark current suppression by introducing an ultrathin insulating layer between the donor and acceptor, where the dark reverse-bias charge injection can be inhibited assisted by interfacial electrostatic modulation while efficient photoresponse is preserved. Based on that, the detector exhibits dark current density of 1.8 × 10−9 A cm−2 and spectral responsivity of 0.52 A W−1 at –1 V, yielding detectivity over 1013 Jones in the near-infrared region. Such low dark current and high detectivity enable detectors to realize noncontact physiological monitoring under NIR light. This work demonstrates the donor–insulator–acceptor architecture for suppressing dark current and improving weak optical detection, providing a general route toward high-performance NIR OPDs.