Self-Powered WO₃-Based Photoelectrochemical Synapse for Object Distance Judgment

Artificial synaptic devices that emulate biological neural systems hold significant promise for neuromorphic computing and brain-inspired intelligence. The development of low-power, cost-effective synaptic devices is crucial for applications in intelligent recognition and real-time monitoring. In this work, WO₃ films were constructed by radio frequency magnetron sputtering, and the self-powered WO₃-based photoelectrochemical synapse was fabricated. The experimental data demonstrate that the WO₃-based photoelectrochemical synapse exhibits self-powered characteristics at 0 bias voltage. This is primarily due to the built-in electric field formed at the semiconductor-electrolyte interface via band bending, which drives the separation of photogenerated carriers and consequently generates the photocurrent. The plasticity conversion between the short-term plasticity and long-term plasticity of photoelectrochemical synapse was achieved by adjusting the number of optical pulses, light power density and frequency.The learning, memory and forgetting behaviors of photoelectrochemical synapses based on WO₃ mapped. More importantly, we further fabricated a 5 × 5 matrix synapses array, successfully simulating the application for object distance judgment. This work highlights the potential of low-energy consumption and low-cost photoelectrochemical synapses, providing a feasible solution for the field of intelligent recognition.