Bias‐Switchable Organic Photodetectors: Opportunities and Challenges for Adaptive, High‐Performance Photodetection

Bias‐switchable organic photodetectors (OPDs) have recently emerged as a versatile optoelectronic platform that enables adaptive photodetection functionalities beyond the capabilities of conventional single‐mode devices. By exploiting the strong field dependence of charge generation, transport, trapping, and extraction in organic semiconductors, a single OPD can reversibly switch between distinct operating regimes under different external biases. This review presents a comprehensive overview of bias‐switchable dual‐mode OPDs and classifies recent progress into four representative categories: (i) bias‐switchable photomultiplication and photovoltaic operation, (ii) bias‐tunable broadband and narrowband photodetection, (iii) bias‐controlled spectral response and detection window, and (iv) bias‐modulated photodetection and photosynapse fusion. We analyze the underlying physical mechanisms governing each dual‐mode behavior, including field‐assisted exciton dissociation, trap‐mediated charge injection, energy barrier modulation, and anisotropic charge transport. Material design strategies, device architectures, and interface engineering approaches that enable reliable and reversible mode switching are systematically discussed. Finally, we highlight the key challenges facing bias‐switchable OPDs, such as operational stability, spectral tunability, and system‐level integration, and provide perspectives on future research directions. By unifying diverse dual‐mode concepts within a common physical framework, this review aims to establish bias‐switchable OPDs as a foundation for adaptive, multifunctional, and intelligent photodetection systems.