Electrochromic properties of NiO-based thin films prepared by sol-gel and dip coating

摘要

A new method for cheical deposition of NiO_xH_y-based films was developed.The films obtained bhave electrochromic properties and good adhesion to the substrate.The precursor sol consists fo an alcoholic solution of NiCl_2 and Ti alcoxide.Films deposited on indium-tin-oxide substrates were prepared by dip coating.The electrochromic efficiency f thin films prepared under different conditions was determined.We report on the effects of (a) Ni concentration,(b) Ti content and 9c) temperature of firing on the electrochromic efficiency.Electrochromic efficiencies measured at #lambda#=632.8 nm of films wit different thicknesses (approx100-200nm) range from 10 to 42 cm~2 C~(-1),with a variation in transmittace up to 30%.The colouring response time is strongly dependent on Ti content.For Ti-doped films this time is5-80 times longer than for undoped ones.The variations in monochromatic transmittance during voltammetric cycles suggest that all the elecric charge consumed by rodox reactions is involved in the colouring process.