An electrochromic (EC) film based on composite of WO3 nanoparticles and copolymer of aniline and o-anisidine was prepared by electrochemical polymerization method on fluorine doped tin oxide (FTO) coated glass substrate. The film was characterized by X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectroscopy. The morphology and thickness of nanocomposite film were characterized as well. The optical transmittance and reflectance of nanocomposite film were investigated in the 200–900 nm wavelength range and EC properties of nanocomposite film were investigated by cyclic voltammetry (CV). The calculation of optical band gaps of film showed the film has directly allowed transition with the values of 2.58 and 3.79 eV. Dispersion parameters were calculated based on the single oscillator model. Finally, important parameters such as dispersion energy, oscillator energy and lattice dielectric constant were determined and compared with the data from other researchers. The obtained results of nanocomposite film can be useful for the optoelectronic applications.
