Sprayed CeO2 thin films for electrochromic applications

Cerium dioxide (CeO2) thin films were prepared by spray pyrolysis using hydrated cerium chloride (CeCl3·7H2O) as source compound. The films prepared at substrate temperatures below 300°C were amorphous, while those prepared at optimal conditions (Ts=500°C,s=5 ml/min) were polycrystalline, cubic in structure, preferentially oriented along the (2 0 0) direction and exhibited a transmittance value greater than 80% in the visible range. The cyclic voltammetry study showed that films of CeO2 deposited on ITO pre-coated glass substrates were capable of charge insertion/extraction when immersed in an electrolyte of propylene carbonate with 1 M LiClO4.These films also remained fully transparent after Li+ intercalation/deintercalation.