A Water‐Resistant Bi‐Based Optoelectronic Synapse for Underwater Neuromorphic Vision

ABSTRACT The exploration of marine environments demands intelligent sensing systems capable of stable operation underwater while performing real‐time visual information processing. Conventional neuromorphic devices, though promising for brain‐inspired computing, suffer from severe degradation in aqueous environments, limiting their application in underwater scenarios. Here, we develop a water‐resistant optoelectronic synapse based on a Rubrene/FA 3 Bi 2 I 9 /ZnO heterojunction, where the hydrophobic Rubrene layer effectively suppresses water infiltration, preserving the microstructure and optoelectronic performance of the lead‐free perovskite even after prolonged water immersion. The device exhibits various synaptic plasticities and can achieve controllable transitions from short‐term memory to long‐term memory by adjusting the parameters of the light pulses. Due to its excellent multi‐spectral response characteristics, we demonstrate the ability to filter redundant information and extract target features in complex light environments. Moreover, a 5 × 5 pixel array exhibits signal‑to‑noise separation, while a 256 × 144 resolution input frames integrated with a fully connected neural network achieves high‑precision classification of aquatic organism movement trajectories with 95.89% accuracy. This work provides a proof‐of‐concept technical path for the development of intelligent visual perception systems and neuromorphic computing hardware suitable for toward future complex underwater environments.