Characterization of reduced graphene oxide: challenges in determining of electrical conductivity for application in conductive inks

Currently, one of the most viable synthesis routes to obtain graphene is the chemical exfoliation, followed by reduction of the product obtained, allowing the production of a larger amount of reduced graphene oxide (rGO). The reduction step is essential in this process, because it allows the partial elimination of oxygenated functional groups inserted in the material and thus recover its conductive properties. The results obtained by the electrical conductivity test showed that the rGO is a conductive material, but the GO (insulating material) also expressed electrical conductivity, being even higher than the rGO. It is known that this factor is linked to the solubility of these materials in water, GO being soluble, allows the uniform measurement of its conductivity, unlike the rGO, whose removal of functional groups prevents the formation of chemical bonds between this material and the water used, negatively affecting the evaluation of the product obtained. (author)