Bias‐Switchable Photomultiplication and Photovoltaic Dual‐Mode Near‐Infrared Organic Photodetector

Abstract

Abstract Photomultiplication‐type organic photodetectors (PM‐OPDs) provide for signal amplification, ideal for detecting faint light, and simplifying detection systems. However, current designs often suffer from slow response speed and elevated dark current. Conversely, photovoltaic‐type organic photodetectors (PV‐OPDs) provide fast response and high specific detectivity ( D * ) but have limited photoresponse. This study presents the synthesis and incorporation of a non‐fullerene acceptor, BFDO‐4F, into the active layer to introduce trap states for capturing photogenerated electrons. The resulting device exhibits dual‐mode characteristic and is bias‐switchable between PV and PM‐modes. In PV‐mode, the OPDs achieve high D * of 1.92 × 10¹ 2 Jones and a response time of 2.83/4.43 µs. In PM‐mode, the OPDs exhibit exceptional external quantum efficiency (EQE) up to 3484% and a D * of up to 1.13 × 10¹ 2 Jones. An on‐chip self‐powered module with PV‐mode pixels driving a PM‐mode pixel is demonstrated, yielding a photocurrent approximately five times higher than the reference device. This approach paves the way for developing multifunctional bias‐switchable dual‐mode on‐chip OPDs, suitable for various applications.