Characterization and properties of electrochromic cobalt oxide thin film prepared by electrodeposition

Electrochromic, anodically and cathodically deposited films were prepared by electro-deposition from Co(NO3)(2) solution onto ITO glass substrate. Anodically deposited films consisted of cobalt oxide and cathodically deposited films consisted of alpha-Co(OH)(2), beta-Co(OH)(2) and CoO which had been originated from the redox reaction of OH- ions existing in the electrolyte. Furthermore, H2O penetrates into the anodically deposited film during the redox reaction. In the case of the cathodically deposited film, Co(OH)(2) is present at the reduction state, whereas at the oxidation state, the film composition changes to a mixture of Co(OH)(2) and CoO.