Effect of hydrothermal and chemical treatment on the optical and electrical properties of reduced graphene oxide deposited on ITO glass

Abstract

In this work, the effect of hydrothermal and chemical treatment on the optical and electrical properties of reduced graphene oxide (RGO) was investigated. Reduced graphene oxide was synthesized by both hydrothermal route using a locally fabricated Teflon lined autoclave and chemical method using hydrazine monohydrate. The thin film was obtained by depositing RGO on Indium Tin Oxide (ITO) glass via spray pyrolysis technique. In RGO hydrothermal, the Raman spectroscopy analysis showed greater restoration of the conjugated networks in graphene sheet. The optical transmittance of RGO hydrothermal and RGO hydrazine decreased after the reduction methods unlike in highly oxidized graphene oxide (HOGO) where eighty percent transmittance was observed at 600 nm and above. For RGO hydrothermal and RGO hydrazine; the optical analysis gave an energy band gap value of 2.1 eV and 2.4 eV respectively, while the resistivity were calculated to be 0.3 Ω m and 0.09 Ω m respectively. This research showed a correlation between the band gap value of RGO and the electrical conductivity. This finding can improve the functionality of RGO as sensing materials. The improved electrical and optical properties of RGO hydrothermal makes it suitable in fiber-optic and opto-electronic applications.