Improving Nonvolatile Properties of Solid-Electrolyte-Based Artificial Synapses via Ion Dynamics Modulation in Organic Electrochemical Transistors

Organic electrochemical transistors (OECTs) have garnered significant attention as artificial synapses due to their ability to emulate synaptic functionalities. While previous research has predominantly focused on modulating the physical properties of the channel materials to enhance synaptic performance, the role of ion dynamics in influencing device characteristics remains underexplored. Effective regulation of ion dynamics is crucial for improving state retention and achieving long-term plasticity (LTP) in these devices. In this study, we propose a strategy to modulate the interactions between polymer semiconductors and ions in solid-electrolyte-based artificial synapses. Our findings indicate that the interplay between semiconductors and doping counterions significantly influences ion transport dynamics, thereby affecting the electrochemical doping and dedoping processes in OECTs. Notably, by suppressing the dedoping process, we achieved enhanced synaptic performances, with devices retaining 64% of the peak current after a retention time of 1000 s. Through the judicious selection of anions and optimization of their interactions with polymer semiconductors, we effectively controlled the dedoping process in OECTs, leading to improved state retention. These insights provide a novel perspective on tuning ion-polymer semiconductor interactions for the development of high-performance synaptic devices, advancing neuromorphic computing applications.