Preparation of reduced graphene oxide thin films from bio-polymer and evaluation of its optical constants

Abstract

Due to its excellent optical, electrical, mechanical and thermal properties, Graphene and Reduced Graphene Oxide have been studied for various applications. Various techniques have also been used to produce high quality thin films like chemical reduction, solution growth, chemical vapor deposition etc. In these techniques mostly toxic, reducible reagents and gases have been used. Herein we report a novel direct and simple procedure for fabrication of reduced graphene oxide thin films without using any hazardous gases or reagents. In this study, reduced graphene oxide thin films were prepared on silicon substrates by a simple wet chemical technique using Shellac Biopolymer as the precursor material followed by annealing at different temperatures. After the formation of the polymer films and subsequent annealing, the structural and morphological evolution of the films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively which indicate the formation of reduced graphene oxide films. The optical constants such as refractive index and extinction coefficient of the films were determined from spectroscopic ellipsometry study which shows lower extinction coefficient and hence higher transparency of the films annealed at 900 °C indicating the suitability of the films for photovoltaic device applications.