Organic Electrochemical Transistors for Emulating Short-Term Synaptic Plasticity and Direction Selectivity
Xiang Wan, Yanyu Hu, Yuanyuan Zhu, Li Zhu, Xing Zhao, Zhihao Yu, Shancheng Yan, Binhong Li, Yong Xu, Huabin Sun
Abstract
Organic electrochemical transistors (OECTs) are now widely investigated for their potential use in brain-inspired neuromorphic computation. In this letter, chitosan-gated OECTs are proposed as the neuromorphic devices. The proton conductive chitosan employed as the dielectric can provide low-voltage operation and synapse-like functions for such device via its electric-double-layer (EDL) capacitive effect. Two wiring schemes are utilized for such devices to emulate two different types of short-term synaptic plasticity: potentiation (STP) and depression (STD). These schemes are further integrated into a novel neuromorphic circuit to implement direction selectivity. The achieved direction selectivity is subsequently employed as a temporal-coding method for the recognition of dynamic handwriting. This study demonstrates the tremendous potential of chitosan-gated OECT in neuromorphic application, and it is expected to accelerate the development of next-generation artificial intelligence systems.