Photodetection‐Photosynapse Multimodal Integrated Device for Synergistic Applications in Encrypted Optical Communication and Image Processing

Integrating photodetector and photosynapse functions into a single device is crucial for advancing image perception in neuromorphic visual systems. However, the disparity in response speeds between these functionalities poses significant challenges for multimodal integration. Here, a multimodal optoelectronic device is presented based on a copper(I) thiocyanate (CuSCN)/poly(N‐vinylcarbazole) (PVK):Y6 composite heterojunction, achieving ultraviolet (UV)‐detection, UV‐synapse, and near‐infrared (NIR)‐detection modes. The device allows seamless switching between modes by precisely tuning the operational voltage and/or adjusting the excitation light wavelength. The charge trapping at the CuSCN/PVK interface, coupled with the controllable movement of photogenerated carriers, enables this multimodal operation. Most importantly, through the synergistic interaction between modes, two optoelectronic applications are demonstrated: frequency‐selective photoresponse for encrypted optical communications and NIR‐assisted enhancement for image recognition. This work not only provides a straightforward method for multimodal operation within a single device but also highlights the potential for synergistic applications in artificial vision systems.