Preparation and characteristics of graphene oxide and its thin films

Various GO samples were prepared using the Hummers method under different synthesis conditions. The obtained GO samples were evaluated for the yields and characterized for the microstructure, surface chemistry, and optical transmittance. The effects of the chemical concentrations, and the addition rates of the chemical and water on the yields and characteristics are reported. The GOs obtained consist of a few layers and exhibit good crystallinity. It was found that the yield was mainly affected by the water dropping rate as well as the NaNO3/KMnO4 ratio. The resulting GOs are also quite similar, regardless of the synthesis conditions, except that the graphite clusters vary slightly in their sizes. GO coatings that exhibit an optical transmittance greater than 80% have been obtained.