A serial flexible humidity sensor based on graphene oxide fibers and quartz crystal resonator

Abstract

A serial flexible humidity sensor based on graphene oxide (GO) fiber and quartz crystal resonator (QCR) was proposed. The serial sensing structure was formed by electrically connecting the QCR with GO fiber embedded in textile in series. This structure became more adjustable by separating the transducing part and sensing part. The feasibility of the serial sensing structure was verified by simulation and experiment. Fabrication of GO fiber was introduced and the electrical properties of GO fiber responding to the relative humidity were measured. The QCR was excited at a frequency of 5.003 MHz. The total frequency shift of the sensor was 91 Hz from 10%RH to 90%RH with a hysteresis of 6.58%. The sensitivity was 2.98 Hz/%RH at 80%RH. The response time was 130 s and the recovery time was 36 s from 20%RH to 80%RH. The sensor has good stability with about 1% variation. This serial sensing structure has the potential to realize a humidity sensor with higher performance.