Bias-Switchable Photomultiplication and Photovoltaic Dual-Mode Flexible Near-Infrared Organic Photodetector

Abstract Photomultiplication-type organic photodetectors (PM-OPDs) offer signal amplification, ideal for faint light detection and simplified systems, but typically face slow response speeds and high dark currents. In contrast, photovoltaic-type OPDs (PV-OPDs) provide fast response and high detectivity (D*) but have limited photoresponse. This study introduces a non-fullerene acceptor, BFDO-4F, into the active layer to create trap states for photogenerated electron capture. The resulting device exhibits dual-mode characteristics and is bias-switchable between PV and PM-modes. It achieves a high D* of 1.92×10¹² Jones and fast response times of 2.83/4.43 µs in PV-mode, and exceptional EQEs up to 3484% in PM-mode. Notably, an on-chip self-powered module featuring PV-mode pixels driving a PM-mode pixel is demonstrated, yielding a photocurrent approximately five times higher than the reference device. This approach establishes a new framework for developing multifunctional, bias-switchable, dual-mode on-chip OPDs, unlocking diverse opportunities in highly integrated advanced sensing applications.