Factors Influencing the Electrochromic Properties of Nickel Oxide Thin Films Derived from Sol-Gel Method by Dip Coating

The synthesis of thin film of nickel oxide is important due to their potential application in eletrochromic displays which can be used in optical displays and as windows controlling the light intensity. Dip coating through sol-gel method is a possible low energy method of coating. Hence this method of film growth has been chosen under various concentration of water, catalyst (acetic acid) and precursor. The films were characterized by XRD, FTIR, thickness profiler and SEM. The films which were synthesized with the concentration of Ni=0.005 molar were found to have low positive current density while the coloration was getting dark when concentration of Ni was increased to 0.015 molar. Increase in concentration of acetic acid decreases the positive current density. Small-Angle X-ray Scattering (SAXS) and density measurements were carried out for the structural characterization of the xerogels. A denser material was obtained at high concentration of acetic acid. The physical and chemical properties of the films and xerogels are well correlated with the electrochemical properties of the films.