Humidity sensitivity investigation of reduced graphene oxide by impedance spectroscopy

In this chapter we report about graphene oxide (GO) and reduced GO (rGO) humidity sensitivity. The GO was reduced by thermal annealing to form rGO, which has increased its conductivity. The effects of the reduction temperature were investigated for both the electrical and humidity sensitivity properties. The electrical properties were studied by electrochemical impedance spectroscopy, which is in particular of high importance to reveal the conduction mechanism of humidity sensitivity. In addition, the morphology and optical properties of rGO films were investigated by atomic force microscopy and UV-Vis-NIR spectroscopy. The reduction temperature plays an important rule for the rGO humidity sensitivity behavior not only by change in film conductivity but also by the transport mechanism.