Influence of the ratio of organic solvent on the deposition of graphene oxide by spin-coating

In this work we investigate influence of the organic solvent addition on the deposition of graphene oxide solution by spin-coating. In order to overcome the poor wettability of polyethylene terephthalate substrate by water graphene oxide suspension we made series of multicomponent solution with different n-methylpyrrolidone to water ratio. We successfully showed possibility and good uniformity of graphene oxide films deposited from the multicomponent solution. According to AFM and Raman spectroscopy we achieved good local uniformity in all cases. The most uniform films were made with 2,35 mg/ml GO concentration. We also found that in case of 0,47 and 1,175 mg/ml concentrations we achieved few-layered graphene oxide with film thickness about 3 nm and less. (paper)