ELECTROCHROMIC BEHAVIOR OF SPUTTERED TITANIUM-OXIDE THIN-FILMS

The electrochromic reaction of titanium oxide films prepared by r.f. s puttering was studied. Chronoamperometric experiments associated with transmittance spectra in LiClO4-propylene carbonate solutions were car ried out and compared with the optical properties of titanium oxide fi lms with different stoichiometries. It was verified that the colour ch anges produced by stoichiometry deviation and by electro-intercalation are similar, because the maximum absorption bands in both cases are c entred at the same wavelength and the molar absorption coefficients ar e similar; these observations can be explained by the mixed valence th eory deduced for non-stoichiometric metallic oxides. The analysis of t he j vs. E and [d(OD)/dt] vs. E potentiodynamic profiles is an interes ting method for studying the kinetic mechanisms of electrochromic reac tions without interference from parallel reactions.