Technology and optoelectronic properties of APCVD Cr2O3 and Mo–Cr mixed oxide thin films

Chromium oxide films have been proposed to serve as counter electrode in electrochromic devices. Previously our studies revealed that APCVD Cr2O3 films exhibit cathodic electrochromic behaviour, so further technological developments in the structure and composition were carried out for studying their electrochromic (EC) properties.Thin Cr2O3 and MoO3–Cr2O3 films were deposited by low-temperature carbonyl CVD process at atmospheric pressure. The deposition temperature of 200 °C was found as optimal since it leads to films with good adhesion to substrates. The chromium oxide films are less investigated, so original studying was necessary to find the correlation between the process parameters, crystal structure and optical quality of the films.The structural characterizations of the films made by FTIR spectroscopy were related to their electrochromic behaviour. Transmittance was measured by UV–VIS spectroscopy and the electrochromic properties were investigated by cyclic voltammetry using different type of electrolytes (type of ions). The results showed that the films have transmittance around 70% in the visible range which is a good initial optical quality for electrochromic applications.