Authors
Haim Kwon, Jihyeon You, Chaeyeon Park, Dong Gue Roe, Ji Hyun Jung, Jeong Ho Cho, Han Young Woo
Published in
Advanced materials (Deerfield Beach, Fla.). Pages e74192. Jul 20, 2026. Epub Jul 20, 2026.
Abstract
Organic electrochemical synaptic transistors (OESTs) are promising building blocks for neuromorphic computing because they leverage volumetric ion-electron coupling to emulate synaptic plasticity. Here, we design sidechain-engineered conjugated polyelectrolytes (CPE-K, CPE-Br, and CPE-Zw) based on a cyclopenta-[2,1-b;3,4-b]-dithiophene-alt-4,7-(2,1,3-benzothiadiazole) (CPDT-BT) donor-acceptor backbone and use them as channel materials in solid-electrolyte-gated OESTs. Spectroelectrochemical measurements demonstrate that cationic CPE-Br achieves a higher and denser doping level than anionic CPE-K and zwitterionic CPE-Zw, enabled by efficient electrolyte ion diffusion throughout the polymer bulk. Temporal polaron transients monitored at 1200 nm reveal that cationic sidechains facilitate volumetric penetration of electrolyte anions to charge-neutralize the positively doped backbone during electrochemical doping. In contrast, anionic sidechains favor rapid local self-compensation through sidechain reorganization, accompanied by limited uptake of external anions. As a consequence, CPE-Br-based OESTs exhibit the highest transconductance, a superior µC* figure of merit, pronounced hysteresis, and long-term synaptic retention with extended long-term potentiation decay times. Collectively, these results establish ionic sidechain engineering as an effective strategy for programming ion ingress, polaron memory, and retention characteristics in OESTs, providing a versatile platform for tailoring synaptic operation in neuromorphic devices.
PMID:
42473777
Bibliographic data and abstract were imported from PubMed on 20 Jul 2026.
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