High‐Rate Deposition of Electrochromic Organotungsten Oxide Thin Films for Flexible Electrochromic Devices by Atmospheric Pressure Plasma Jet: The Effect of Substrate Distance

Abstract

High‐rate deposition of electrochromic organotungsten oxide (WOxCy) films onto flexible PET (polyethylene terephthalate)/ITO (indium tin oxide) substrates by atmospheric pressure‐plasma enhanced chemical vapor deposition (AP‐PECVD) with atmospheric pressure plasma jet (APPJ) under various substrate distances is investigated. A precursor (tungsten carbonyl, W(CO)6, TC) vapor, carried by argon gas, is injected into air plasma torch for the synthesis of WOxCy films. Uniform light modulation up to 1 cm wide on PET/ITO/WOxCy is produced, while the moving PET/ITO substrate is exposed to a 0.3 cm diameter plasma torch at room temperature (≈23 °C) and atmospheric pressure. The porous APPJ‐synthesized WOxCy films result in fast responses using potential steps for coloration of 11.5 s at −1V and bleaching of 7.2 s at +1V, respectively. APPJ‐synthesized WOxCy films offer noteworthy electrochromic performance in light modulation with up to 73.0% of transmittance variation, optical density change of 0.72 and coloration efficiency of 67.7 cm2 · C−1 at a wavelength of 800 nm.