Structural and optical properties of molybdenum–tungsten mixed oxide thin films deposited by the sol-gel technique

Sol-gel derived molybdenum–tungsten (Mo–W) mixed oxides were investigated by transmission electron microscopy in order to study the dependence of their structural and morphological properties on the relative percentage of the constituent compounds. Optical measurements were performed in the 200–800 nm wavelength range to correlate thin film structure and optical properties. Moreover, the values of the band gap energy were estimated as a function of the percentage of the W precursors added in the solution.