Electrochemical State Reconfiguration in Vertical Opto-ionic Transistors for Adaptive Optoelectronic Computing

The ability to dynamically reconfigure a single device between sensing and computing functions could fundamentally simplify in-sensor vision architectures, yet achieving electrically programmable transitions between volatile photodetection and persistent synaptic processing remains challenging. Here, we establish an electrochemical state-reconfiguration strategy in a vertical opto-ionic electrochemical transistor (VOET) that enables reversible transformation between these two information-processing modes. The VOET integrates a porous sol-gel-derived ZnO semiconductor with an ionic-liquid gate in a vertically stacked multifinger architecture, enabling efficient volumetric electrochemical doping and coupling ionic dynamics with electronic transport throughout the channel. In the undoped state, the device exhibits volatile ultraviolet photodetection with an ON/OFF current ratio of 6 × 103, a responsivity of 132 mA/W, and a peak shot-noise-limited specific detectivity of 3.9 × 1010 Jones. Electrochemical ion doping switches the same transistor into a persistent photoconductive state, enabling nonvolatile optoelectronic synaptic operation with a post-tetanic potentiation index of up to 1100% and multidimensional spike-dependent plasticity governed by stimulus rate, duration, number, and intensity. Neural-network simulations using experimentally measured synaptic characteristics further demonstrate handwritten-digit recognition. These results reveal electrochemical state reconfiguration as a route to programmable transformation of transistor functionality, providing a compact platform for adaptive optoelectronic sensing, memory, and neuromorphic computing.