Graphene oxide and its films produced using a nebulizer spray coating method

• Graphene oxide films produced using a novel nebulizer spray coating method. • Partially reduced films studied as a function of annealing temperature and atmosphere. • Characterization by complementary SEM, EDS, AFM, XRD, UV-vis, FTIR, XPS , Raman & PL . • Luminescence decreased, Raman I D /I G ratio decreased for increased anneal temperature. Graphene oxide was prepared by the modified Hummers’ method. Structural analysis using X-ray diffraction and Raman spectroscopy revealed that sheets of the material were multi-stacked and narrow along the basal plane. Oxygen functional groups were identified using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Photoluminescence measurements showed broad visible emission at ∼550 nm. Thin films were produced using a nebulizer spray coating system which is simple, flexible and inexpensive and avoids the need to add further organic chemicals to the precursor solution or to specially prepare the Si substrate to improve adhesion. The as-deposited films exhibited blue photoluminescence centred at ∼425 nm, which was indicative that some reduction of the graphene oxide already occurred during the deposition process onto the substrate heated to 70 °C. The effect of annealing the films at temperatures between 300-600 °C and in different atmospheres on their morphology, Raman spectra and luminescence was investigated.