COUNTER ELECTRODES IN TRANSMISSIVE ELECTROCHROMIC LIGHT MODULATORS

Transmissive electrochromic light modulators require two electrodes to be in the light path, a primary electrochromic material and a charge-balancing counter-electrode (CE). Two insertion-type CEs are reviewed, IrO2, for operation in protic environments, and V2O5 for operation in nonaqueous, Li-based electrolytes. Both undergo anodic coloration processes which complement the blue cathodic coloration of WO3. Reversible and deep visible light transmission modulation has been demonstrated for WO3/IrO2 and WO3/V2O5 series combinations.