Ultra-conformal skin electrodes with synergistically enhanced conductivity for long-time and low-motion artifact epidermal electrophysiology

TLDR

Wearable healthcare requires accurate, imperceptible electrophysiological monitoring, yet conventional stiff pregelled electrodes cause discomfort and motion artifacts. The study introduces a ~100 nm ultra‑thin dry epidermal electrode that adheres conformably to skin for accurate electrophysiological measurement. Its performance arises from a synergistic graphene–PEDOT:PSS interface that promotes molecular ordering and charge transfer via strong π‑π interactions. The electrode exhibits low sheet resistance, high transparency, and mechano‑electrical stability, enabling accurate, low‑artifact monitoring of facial and brain activity for long‑term health and human‑machine interfacing.

Abstract

Abstract Accurate and imperceptible monitoring of electrophysiological signals is of primary importance for wearable healthcare. Stiff and bulky pregelled electrodes are now commonly used in clinical diagnosis, causing severe discomfort to users for long-time using as well as artifact signals in motion. Here, we report a ~100 nm ultra-thin dry epidermal electrode that is able to conformably adhere to skin and accurately measure electrophysiological signals. It showed low sheet resistance (~24 Ω/sq, 4142 S/cm), high transparency, and mechano-electrical stability. The enhanced optoelectronic performance was due to the synergistic effect between graphene and poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), which induced a high degree of molecular ordering on PEDOT and charge transfer on graphene by strong π-π interaction. Together with ultra-thin nature, this dry epidermal electrode is able to accurately monitor electrophysiological signals such as facial skin and brain activity with low-motion artifact, enabling human-machine interfacing and long-time mental/physical health monitoring.