Vapor-Coated Monofilament Fibers for Embroidered Electrochemical Transistor Arrays on Fabrics

Fiber-based electrochemical transistors can be embroidered onto fabrics for wearable and implantable bioelectronics. However, the active channel length of known fiber-based electrochemical transistors is defined by the dynamic contact area between the conductive fiber and a liquid electrolyte, meaning that existing iterations cannot be reliably operated upon immersion in biological media. A proof-of-concept parallel-junction electrochemical transistor on a silk fabric with a fixed, micrometer-sized channel length that is independent of electrolyte contact area is reported. A high on/off ratio of 1000, and notable transconductance value of 100 mu S at zero gate voltage and low applied drain bias (0.7 V) is obtained, making this device amenable to subsequent incorporation into low-power-consuming integrated circuits. Large-area arrays of this transistor can be rapidly created by straight-stitching a monofilament fiber channel onto a fabric substrate, meaning that simple embroidery approaches can be used to fabricate spatially resolved electrode arrays for electrophysiological applications.