Synthesis and characterization of conductive few layered graphene nanosheets using an anionic electrochemical intercalation and exfoliation technique

Abstract

The mechanism of electrochemical intercalation resulting in the expansion and exfoliation behavior of the pyrolytic graphite sheets is described. In this paper, an efficient and simple process of the intercalation of perchlorate anions from a simple protic solvent at various electrolytic concentrations using a two electrode system is reported. The intercalate concentration plays a major role in the as-prepared exfoliated few layered graphene nanosheets (FLGNSs). The in situ oxygenation and hydroxylation of the FLGNSs has been painstakingly analyzed using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and UV-visible spectroscopy. Furthermore, the nature of the exfoliated FLGNSs colloidal was determined using field emission scanning electron microscopy, transmission electron microscopy as well as dynamic light scattering techniques. From the various analytical results obtained, it is found that the synthesized GNSs consist of FLGNSs with surface oxygenation. The extent of the surface oxygenation was found to be increased with an increase in the concentration of the intercalate. The exfoliated colloidal graphene obtained at an optimum electrolytic condition shows a stable dispersion and the highest conductivity was ∼0.87 mS cm⁻¹. Furthermore, the conductivity of the oven dried colloidal graphene on a fluoride treated glass slide was successfully used in a light emitting diode fabrication test.