Thickness of graphene oxide-based materials as a control parameter

Abstract

Graphene oxide-based materials have been widely used for different applications, such as: biotechnology, electronics, and adsorption or separation technologies amongst other uses. In this study, graphite oxide (GrO), large graphene oxide (lGO) and small graphene oxide (sGO) were synthesized. Monolayer large graphene oxide (mlGO) was detected and isolated in this synthesis prior to lGO separation from GrO. A battery of techniques was applied to elucidate their physicochemical properties. Morphological results acquired by high resolution scanning electron microscopy, transmission electron microscopy and scanning transmission electron microscopy demonstrated the flat and planar structures of these materials. Similar lateral dimensions were found for lGO and mlGO unlike sGO. However, based on atomic force microscopy studies, it was able to demonstrate that lGO presented thicker laminar structures than mlGO. Their crystallography evaluated by x-ray diffraction corroborated the results obtained by the atomic force microscopy studies, since mlGO displayed a diffractogram characteristic of highly exfoliated material. Additionally, Turbiscan experiments revealed a more significant impact from the thickness of these materials in contrast to their lateral dimensions in their colloidal stability properties in aqueous solution. Characterization results were correlated with the optical band gap obtained from the Tauc method of their UV-vis absorption spectra, which could be implemented to characterize in-line the production of these carbon materials to optoelectronic devices.