Thin films produced by dip-coating from tungsten alkoxide solutions are of interest for large area electrochromic (switchable) window coatings. The window systems consist, in part, of a layer of tungsten oxide (WO3) on a layer of indium tin oxide (ITO) on glass substrate. Sol-gel processing has several advantages over other preparation techniques. However, there is the possibility of hydrocarbon residue within the films. Such carbon may restrict the electrochromic performance of the films. Rutherford backscattering spectroscopy (RBS) has been used for determining elemental composition and depth profiles in these film structures. The spectra confirm that sol-gel samples contain a substantial level of a light element, such as carbon. Auger electron spectroscopy supports the estimate obtained for the carbon content. The residual carbon can, however, be burnt out by firing at > 500 degree(s)C. Under certain conditions, a sub-layering is seen in the depth profiles.
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