Unidirectional Bias‐Switchable Dual‐Mode Organic Photodetectors Enables Secure Communication and Gesture Simulation

Abstract The development of dual‐mode organic photodetectors (OPDs) greatly improves its functionality by enabling selective spectral detection. This study presents a unidirectional bias‐switchable dual‐mode OPD that leverages selective carrier extraction through the manipulation of light field distributions and non‐equilibrium transport dynamics. This dual‐mode OPD features a simple single‐layer structure, allowing for straightforward one‐sided light incidence and without the need for voltage polarity switching. By optimizing the blend of poly(4‐butyl‐phenyl‐diphenyl‐amine) and non‐fullerene acceptor Y6, the device achieves efficient single‐band detection of ultraviolet (UV) light at low bias and dual‐band detection of UV and near‐infrared light at high bias. This versatility not only streamlines device architecture but also facilitates secure optical communication and gesture simulation, making it a valuable tool for advancing organic optoelectronics. The proposed strategy demonstrates universal applicability, paving the way for enhanced security and functionality in digital communication systems.