High performance humidity sensor based on a graphene oxide–chitosan composite

Abstract

In this study, we have proposed an advanced humidity sensor based on a composite of chitosan (CS) and graphene oxide (GO), prepared by the drop casting method. Graphene oxide–chitosan (GO–CS) films with varying volumetric ratios, along with pure GO and CS films, were prepared and extensively characterized using XRD, Raman, FTIR, SEM, XPS, and water contact angle to study their structural and morphological properties. Comparative analysis of humidity sensing parameters of all prepared films revealed that the film with a volumetric ratio of 4 : 1 (GOCS-2) performs best among all of them, which is attributed to the synergistic interaction between GO and CS. The optimized composite demonstrates high sensitivity, rapid response/recovery time, low hysteresis, and excellent repeatability as compared to pure GO and CS films. This study revealed that the enhanced performance is mainly driven by the increased hydrophilic functional groups and adsorption sites in the GO–CS composites. The optimized composite is proposed to be a promising candidate for the development of cost-effective and high-performance humidity sensors.