Enhancing Synaptic Plasticity and Multistate Retention of Organic Neuromorphic Devices Using Anion‐Excessive Gel Electrolyte

Abstract Recently, organic electrochemical transistor (OECT)‐based neuromorphic devices have attracted considerable attention due to their diverse advantages such as ionic‐electronic coupling, low voltage operation, gradual and tunable conductance change, mechanical flexibility, and biocompatibility. However, for practical implementation in artificial neural networks (ANNs), key issues such as limited long‐term plasticity (LTP) and weak multistate retention need to be addressed. These challenges mainly stem from the disruption of electrical equilibrium of the electrolyte due to the penetration of ions into the active layer. Here, anion‐excessive gel‐based organic synaptic transistors (AEG‐OSTs) using an electrolyte containing both molecular dopant and ionic liquid/salt are developed to overcome these limitations. AEG‐OSTs exhibit greatly enhanced LTP characteristics and multistate retent…