Electrochromism of anodic iridium oxide films on transparent substrates

Anodic iridium oxide films (AIROF’s) can be grown and operated on transparent substrates. Using SnO2-coated glass as the substrate we can monitor large, rapid, and persistent variations of the light intensity transmitted through the AIROF. The voltammogram of the AIROF on SnO2-coated glass is essentially identical to that of an AIROF on iridium. This proves that the electrochemistry producing the coloration does not involve the substrate.