Effect of substrate temperature on electrochromic properties of spray-deposited Ir-oxide thin films

Electrochromic iridium oxide thin films were prepared by using a simple and inexpensive spray pyrolysis technique onto fluorine doped tin oxide (FTO)-coated glass substrates, from iridium chloride solution. The substrate temperature was varied between 250 and 400 8C. The as-deposited samples were amorphous. The electrochromic properties of thin films were studied in aqueous electrolyte (0.5N H2SO4) using cyclic voltammetry (CV), chronoamperometry (CA) and spectroelectrochemical techniques. The films exhibit anodic electrochromism upon intercalation and deintercalation of H+ ions. The colouration efficiency at 630 nm was calculated and found maximum for I250 sample, owing its hydration.