Graphene oxide/cellulose nanofiber-based capacitive humidity sensor with high sensitivity

A capacitive humidity sensor based on graphene oxide/cellulose nanofibers (GO/CNF) is proposed in this work. The sensing characteristics of the humidity sensor at different relative humidities (RH) are investigated. The results demonstrate that the GO/CNF-based sensor has a high humidity sensitivity (1146.8 pF /% RH), which is nearly 19 times higher than the pure CNF sensor and almost 2.6 times greater than the pure GO sensor. This is due to the fact that the incorporation of CNF into the GO/CNF film introduces additional hydrophilic functional groups and causes an increase in film roughness and wrinkling. This increases the number of water molecule adsorption sites on the GO/CNF composite film on the one hand, and expands the contact area of the GO/CNF composite film with water molecules on the other hand, resulting in a GO/CNF-based humidity sensor with high response sensitivity. Moreover, the sensor shows rapid response and recovery rates, as well as low hysteresis characteristics. Therefore, this research suggests that GO/CNF hybrid films possess considerable potential for the production of high-performance humidity sensors.