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The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO 3 –SiO 2 thin films

2007; Institute of Physics; Volume: 40; Issue: 7 Linguagem: Inglês

10.1088/0022-3727/40/7/034

1361-6463

Naimeh Naseri, R. Azimirad, Omid Akhavan, Alireza Z. Moshfegh,

Catalysis and Oxidation Reactions

WO3–SiO2 compound thin films were deposited on glass substrates using the sol–gel method, and then all the samples were dried at 100 °C and annealed at 400 °C in air. The effect of WO3 concentration on the hydrophilicity of WO3–SiO2 compound films was studied for the first time and it was shown that the films containing 85 mol% of the concentration possessed a superhydrophilic surface without UV or visible irradiation. Optical properties of the films such as transmittance, reflectance and bandgap energy were investigated using a UV–visible spectrophotometer. According to atomic force microscopy, the surface ratio was maximized in 85 mol% concentration of WO3 similar to hydrophilicity. Surface chemical states of the films were studied by x-ray photoelectron spectroscopy, which determined the stoichiometry of the deposited thin films. X-ray diffraction patterns showed that the compound thin films constituted of nanocrystalline tungsten oxide grains with 60–10 nm grain size depending on the WO3 concentration.