Influence of Dopant Concentration on the Electrochromic Properties of Tungsten Oxide Thin Films

In order to achieve neutral coloration suitable for smart window applications WO3 thin films modified by V2O5 doping were deposited using RF magnetron sputtering method with 100 W RF power at room temperature (RT). The influence of dopant concentration on the structural and electrochromic performance have been investigated. Amorphous structure was revealed by the surface characteristics facilitates electrochromic process. Uniformly distributed channels between the aggregated grains provide shorter path ways to enhance coloration efficiency. PL emission presented higher photonic efficiency for 2% of V2O5 doped WO3 film. Reversible color change between transparent oxidized and deep blue colored reduced state depicted faster ion intercalation / deintercalation kinetics and faster switching responses with the bleaching time of 3.3 s and coloration time of 4.1 s. Better reversibility of 59.10 %, larger photopic contrast ratio of 2.29 and greater coloration efficiency of 66.75 cm2C−1 at 630 nm unveiled by 2% of V2O5 doping, makes the film promising for practical applications.