Cold RF oxygen plasma treatment of graphene oxide films

Oxygen radio-frequency (RF) plasma technique is one of the most novel directions used to improve the physical and chemical properties of graphene oxide (GO). Herein, plasma treatment is used to enhance the chemical functionalization and reduced levels of the GO material for electronic and solar cell applications. GO films were chemically synthesized with high quality and uniformity. Then, they exposed to surface modification using RF oxygen plasma at a processing power of 100 W at different processing times. The microstructure and surface chemistry of the GO films were characterized by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Moreover, the effect of oxygen plasma on the thermal stability, surface roughness, contact angle, work of adhesion, wettability, spreading coefficient, and electrical properties have been studied. The results revealed a decrease in the amount of oxygen-containing groups (such as epoxides, carbonyls, and carboxyl groups) from 48.8% in pristine GO to 36.15% after 5 min of oxygen plasma treatment. Besides, the carbonyls groups (C = O) disappeared while new chemical bonds were created compared to the pristine GO film such as hybridized carbon atoms (SP3) and carboxyl's (O–C = O). Accordingly, the electrical conductivity increases from 0.11 S/m of pristine GO to an optimum value of 0.46 S/m after 5 min of plasma treatment, as a result of the incorporation of high amount of carboxyl, hydroxyl and carbonyl groups. The current results indicate that the properties of GO can be tuned by varying the degree of oxidation, which may pave the way for new developments in GO-based applications.