Ultrahigh Linear Sensitivity of Capacitive Humidity Sensor Base on Bilayer Structure of Graphene Oxide

Abstract

Capacitive humidity sensor is designed on interdigitage electrodes (IDEs) by lithography process for nice humidity absorption and desorption. This paper proposed the IDEs humidity sensor base on bilayers sensing of graphene oxide (GO) structure by dip coating method. Each GO layer is held by covalent-bond forces from adhesive layer. It demonstrates durable of sensing layer material. Raman spectroscopy analysis is exhibited on GO presence and scanning electron microscope (SEM) explored on the GO bilayers structure. The IDEs/GO bilayers humidity sensor demonstrated ultrahigh sensitivity (up to 2014.61%) and linear responses at relative humidity (RH) ranges 10 to 70% while IDEs/GO single layer showed exponential responses. Moreover, it significantly improved on response (12 sec) and recovery times (18sec), a little hysteresis (up to 46.77%) and stable repeatability. Finally, the durable of IDEs/GO bilayers humidity sensor is exhibited by long-term ability measurement (time period 35 days). Therefore, these characteristics of GO bilayers structure base on adhesive layer are clearly demonstrated high performances for alternatively used with humidity sensor applications.