Wavelength‐Modulated Multi‐Functional Photoresponse for Image Processing and Encryption

ABSTRACT Photonic memory with synapse‐like behaviors and fast optical switching is essential for neuromorphic information processing and optoelectronic signal detection, respectively. Their integration is highly attractive, as it enables advanced functionalities such as wavelength‐selective optical storage and secure photonic encryption. However, photonic memory typically relies on slow carrier trapping and recombination processes, whereas optical switching requires rapid carrier separation and transport, making their coexistence within a simple device architecture intrinsically challenging. Here, we demonstrate a multifunctional organic photonic platform based on two complementary heterojunctions: PTCDI‐C 13 /F 16 CuPc (n‐n type) and p ‐7P/F 16 CuPc (p‐n type). The n‐n junction enables stable positive‐photoconductance optical memory, while the p‐n junction supports negative‐photoconductance–based memory erasing through gate‐assisted interfacial recombination. Under long‐wavelength illumination, both heterojunctions function as fast photodetectors with response times of τ ON < 8 ms and τ OFF ≤ 18 ms. Leveraging the bidirectional photonic memory and fast switching, the devices achieve 98.3% image recognition accuracy and enable a Continuously Learning Encryption System (CoLES). This work establishes a materials‐based strategy for integrating slow optical memory and fast switching toward secure in‐sensor photonic computing.