Ordered fiber ionic pathways for wide-frequency regulation in electrolyte-gated transistors for bio-signal perception

Abstract

Electrolyte-gated transistors (EGTs) with organic polymer electrolytes are promising candidates for wearable bioelectronic devices, owing to their inherent flexibility and biocompatibility. However, their low frequency response (<100 Hz) impedes the effective processing of dynamic biological signals such as surface electromyography (sEMG) and audio signals. Here, we address this challenge by employing ordered nanofibers to create oriented ionic conduction pathways within a quasi-solid polymer electrolyte. This approach preserves the high capacitance of the electrolyte across an extended frequency range, enabling EGTs to respond efficiently to signals spanning from 1 Hz to 1 kHz while demonstrating synaptic plasticity. Additionally, the integration of an interdigital electrode design facilitates an intrinsic filtering capability, realized by selecting electrodes at varying distances from the channel. The resulting device achieves precise detection and processing of sEMG and audio signals, while replicating key neuromorphic features such as muscle synaptic behavior and auditory synaptic fatigue responses. This work broadens the operational frequency range of quasi-solid electrolyte-based EGTs and enriches their functionality as bioinspired synaptic devices, offering a versatile platform for interfacing electronic systems with biological signals.