Highly Aligned Polymer Nanowire-Based Fin Architecture for Enhanced Functionality of Organic Electrochemical Transistors in Neuromorphic Computing

Abstract

Despite rapid advances in organic neuromorphic electronics, achieving linear and stable synaptic plasticity in organic electrochemical transistors (OECTs) remains challenging. Here, we show that imposing high alignment and nanoscale confinement in Poly[2,5-bis(3tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT-C 14) conjugated polymer nanowires (NWs)-organized as a fin architecture-directly enhances ion-polymer interactions and regulates ion transport, thereby improving OECT functionality relevant to neuromorphic computing. Uniform, highly aligned NWs are formed by solution nanomolding using a polydimethylsiloxane (PDMS) mold. The resulting fin-structured OECTs (FinOECTs) exhibit a μC* value, where μC* is the product of the volumetric capacitance (C*) and charge carrier mobility (μ), of 10.24 F V⁻ 1 s⁻ 1 cm⁻ 1, approximately twofold higher than film-based control devices. Structural analysis confirms increased crystallinity (coherence length 508.9 Å) and tighter π-π stacking, consistent with confinement-driven ordering that supports efficient mixed conduction. Most importantly, the alignment-driven fin geometry yields highly linear synaptic responses in both long-term potentiation (LTP) and long-term depression (LTD) (R 2 of 0.997), by moderating otherwise rapid ion diffusion at the NW-ion-gel interface. The devices also exhibit robust long-term memory (LTM), retaining 46.16% of the excitatory postsynaptic current after1,000 s. Finally, FinOECT-based reservoir computing attains a structural similarity index of 0.80 on a 16×16 pattern recognition task. These results establish highly aligned polymeric NW fin architectures as a materials-and structure-level route to linear, durable and energy-efficient OECT-based neuromorphic computing system.