A high-performance humidity sensor based on in-PCB interdigitated electrodes

摘要

This paper presents a low-cost and high-performance humidity sensor based on interdigitated electrodes (IDE). Compared to common IDE sensors with such substrates as silicon, ceramic, polyimide, and polyethylene terephthalate (PET), the proposed sensor employs printed circuit board (PCB) as the substrate, offering easy electrical connection to the readout circuit and great potential as a low-cost and highly integrated sensing platform. The IDE sensor with eight pairs of comb-like twin electrodes is designed and fabricated on a PCB by the standard PCB manufacturing process. A mixture of dielectric graphene oxide and conductive MXene has been used as the moisture sensing material due to its strong hydrophilicity and tunable conductivity. Upon functionalization by the sensing material, the IDE structure achieves the capability of converting changes in the relative humidity (RH) into resistance shifts. The resistive response of the sensor to the varying RH levels from 11% to 84% has been evaluated. The sensor exhibits a high RH sensitivity of 1.245%/%RH, and also fast response/recovery and low hysteresis.