The Polymer Society of Korea

Abstract

Organic mixed ionic-electronic conductors (OMIECs) are key materials in organic electrochemical transistors (OECTs) and neuromorphic devices due to their dual ion-electron transport capabilities. While OECTs have been widely studied for emulating synaptic behavior, organic electrochemical diodes (OECDs) offer a promising alternative architecture for neuromorphic computing. In this study, we present the impact of a vertical OECD structure on synaptic plasticity. By applying tailored input signals and stimulation protocols, we demonstrate fundamental neuromorphic functions. Both liquid and solid-state electrolytes were evaluated, revealing that ionic size significantly influences long-term potentiation/depression and retention behavior. This highlights the tunability of synaptic responses through ionic control. These vertical OECDs exhibit promising synaptic properties and provide a scalable path forward for polymer-based neuromorphic computing platforms.