Ultra-lightweight, highly permeable, and waterproof fibrous organic electrochemical transistors for on-skin bioelectronics

Abstract

Recently emerged on-skin electronics with applications in human-machine interfaces and on-body healthy monitoring call for the development of high-performance skin-like electrodes and semiconducting polymers. The development of waterproof and breathable membranes that can provide a high level of protection for human skins and a comfortable contact between electronics and skin are the pressing demands for on-skin electronics. However, major challenges remain, such as the limited mechanical durability and permeability of gas and liquid, hindering long-term stability and reusability. Herein, we report a fibrous electrolyte containing polymer matrix and ionic liquid, which is highly robust, breathable, waterproof, and conformal with human skin. Serving as fibrous substrate and electrolyte of organic electrochemical transistors (OECTs), a high transconductance of ~0.8 mS, stability over pulsing and time (~1000 cycles and 30 days) were achieved. The softness of fibrous OECTs enables a comfortable contact after attaching to human skin, which can reduce the interfacial impedance to achieve a high-quality local amplification of the electrocardiography signals (signal-to-noise ratio of 21.7 dB) even in skin squeezed state or after one week. These results indicated that our fibrous OECTs have huge potential for versatile on-skin electronics such as non-invasive medical monitoring, soft sensors, and textile electronics.