The Polymer Society of Korea

Abstract

Carbon nanotube (CNT)-based synaptic transistors are promising for neuromorphic electronics due to their high mobility and solution processability. To overcome the complex conventional CNT sorting processes, unsorted CNT (UCNT) devices have been proposed as a scalable and cost-effective alternative. However, their operation is largely limited to short-term plasticity by rapid back-diffusion of mobile ions. In this work, we introduce a polymer-assisted strategy to overcome this limitation by introducing block copolymer dispersant, which imposes steric hindrance on ionic transport within the CNT network. As a result, ionic back-diffusion is effectively suppressed, leading to markedly enhanced conductance retention and the emergence of stable and linear long-term potentiation and depression behaviors. These results demonstrate a clear advancement of UCNT synaptic transistors and highlight polymer-induced ionic confinement as an effective route toward long-term synaptic memory devices.