Deposited structures of reduced graphene oxide onto glass substrates influenced by solvents and cleaning reagents

In this paper, a study on the deposition formation of reduced graphene oxide (rGO) via drop casting onto glass substrates were carried out. Two different solvents (deionised water (DIW) and N-Methyl-2-Pyrrolidone (NMP)) and cleaning reagents (RCA-Standard Clean-1 (RCA-1) and isopropyl alcohol (IPA)) were used for the investigation. The deposition structures were analysed by using high-power and scanning electron microscopes. Ultraviolet-visible (UV-Vis) spectroscopy was used to validate the authenticity of the as-prepared rGO. Results indicated that the as-prepared rGO from DIW was more suitable to be deposited on the glass substrate cleaned with IPA compared to RCA-1, yielding better uniformity and a high density of rGO coverage. Meanwhile, the rGO suspension prepared from NMP and cleaned with RCA-1 was more suitable to be deposited on the glass substrate. The combination of solvents and cleaning reagents affected the glass substrates surfaces where a different in deposition structured were observed. Furthermore, a concentration of 1 mg/mL was considered as a very high concentration to prepare the rGO colloidal suspension where such a concentration results in a poor exfoliation.