Modelling the Structure and Optical Properties of Reduced Graphene Oxide Produced by Laser Ablation: Insights from XPS and Time-Dependent DFT

Abstract

Graphene derivatives such as reduced graphene oxide and graphene-based composites are regarded as highly promising materials for optoelectronics and photodetection applications. Recently, considerable interest has arisen in using facile and environmentally friendly methods of graphene production. Despite significant progress in experimental studies of graphene and graphene-based composites, some fundamental questions about their structures, and the interaction between components in these systems, remain open. In the present work, several atomistic models of oxidized graphene fragments have been proposed based on XPS compositional analysis and DFT calculations, representing reduced graphene oxide produced by laser irradiation. The composition of the oxygen-containing functional groups, their equilibrium configuration and influence on the electronic and optical properties of graphene sheets were determined. The nature of the low-lying excited states, as well as the photoactive regions, has also been studied for the proposed models. The calculated absorption spectra of the graphene sheets were compared with experimental UV-Vis spectrum of rGO produced by laser ablation.