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

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.