Synthesis properties and applications of graphene oxide derivatives and their nanocomposites

Abstract

Graphene family materials such as, graphene oxide (GO), reduced graphene oxide (rGO) and graphene quantum dots (GQD) are extensively studied due to their fascinating properties such as larger surface area, surface functionalities, tunable bandgap, enhanced electrical and optical properties. These facinating properties find many applications in various fields like energy storage, sensing, water purification, biomedical and so on. In this thesis work, GO was synthesized by chemical exfoliation of graphite through modified Hummer s method. Thermal reduction of GO was carried out to improve the physiochemical characteristics of GO through de-oxygenation and restoration of and#960; conjugation. Further, the reduction temperature was optimized to obtain the porous graphene network (PGN) like structure. The surface morphology and structural transformation of GO during oxo-reduction stages are analysed. This work highlights a simple and template free method to synthesize PGN compared to conventional template assisted techniques. Further, a simple method to get the conductive rGO film and a method to analyze the electron transport behaviour is acheived. The gradual and controllable thermal reduction of GO film formed by drop-casting method was carried out. Here, the role of functional groups on the evolution of electrical conductance during reduction has been investigated by correlating the IR modes and electrical conductivity. This method enables one to control the electrical conductance of rGO by simply controlling the degree of reduction.