Optical, structural, and electrochromic properties of cobalt oxide films prepared via the sol–gel route

Cobalt oxide films were prepared by the sol–gel dip-coating method on glass and conducting (fluorine-doped tin oxide) glass substrates for electrochromic applications. XRD studies revealed that coated films comprising two to 10 layers were amorphous. FTIR spectra exhibited peaks attributable to Co–O vibrations. SEM images revealed the formation of nanopores in the surface of four-layered films. The electrochromic properties of the films were studied using cyclic voltammetry and in situ spectroelectrochemical techniques. The four-layered CoO film exhibited the highest anodic diffusion coefficient among all the films (3.50×10−13cm2/s) and optical transmission variation of 26%.