High-transconductance fiber-based organic electrochemical transistors for wearable biological monitoring using semiconductor yarn electrodes

Fiber-based organic electrochemical transistors (F-OECTs) have recently become important wearable devices for physiological monitoring. However, F-OECTs are limited by low electrical performance. In this study, a semiconductor yarn electrode was used to fabricate a high-performance F-OECT. Specifically, MWCNTs/PPy composite flexible electrodes were developed on a cotton yarn substrate and integrated with PEDOT:PSS as an organic semiconductor material. This approach improved the electrical conductivity and mechanical flexibility of the F-OECT, ensured multi-angle bending stability, and enhanced wearable comfort. At the same time, by constructing an MWCNT/PPy/PEDOT conductive synergistic network, the transconductance value (24.12 mS) and switching ratio (68.82) of F-OECT were significantly enhanced with excellent stability. The performance was up to 8 times better than that of existing fiber-based devices. After the gate modification, modern knitting technology wove cotton yarn and sensing yarn into smart electronic textiles for rapid, real-time glucose monitoring in human urine, and this approach showed great potential for non-invasive biomonitoring applications.