A Piezoelectric Resonant Humidity Sensor with Enhanced Sensitivity Based on High Mode Driven by Interdigital Transducers Coated with Uniform Graphene Oxide Film

This paper reports a high-performance humidity sensor using high mode of piezoelectric resonator driven by interdigital transducers (IDT) with a thin graphene oxide (GO) film. Innovative claims include: (1) the higher relative sensitivity using high mode driven by IDT compared with normal configuration. (2) monitoring of humidity variation with short response/recovery time. The results demonstrate an improved sensitivity (668 ppm) at 10%-90% relative humidity, higher than that (436 ppm) of normal configuration with resonant frequency of 70 MHz. The sensor also shows short response (~7 s)/recovery (~13 s) time.