Lithium electrochromic properties of atmospheric pressure plasma jet-synthesized tungsten/molybdenum-mixed oxide films for flexible electrochromic device

Abstract

An investigation is conducted into the enhanced lithium electrochromic performance of flexible tungsten/molybdenum-mixed oxide (WMo x O y C z ) films deposited onto 40 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates, using a low temperature (~23 °C) atmospheric pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet at various substrate distances. The rapid synthesis of flexible WMo x O y C z films is performed by injecting the mixed hexacarbonyl and precursors W(CO)6 and Mo(CO)6 into an air plasma jet and exposing the substrate in the plasmas for short exposure durations (19–34 s) at various substrate distances. The flexible WMo x O y C z films possess the remarkable Li+ ion electrochromic performance, even though after being bent 360° around a 2.5-cm diameter rod for 1,000 cycles and tested for 200 cycles of reversible Li+ ion intercalation and deintercalation in a 1-M LiClO4-propylene carbonate electrolyte, respectively, by a potential sweep switching at the scan rates of ±50 mV/s from the potential of −1 to 1 V and a potential step switching at the potentials of −1 and 1 V. Significant optical modulation and optical density change of up to 71.2 % and 0.73 at a wavelength of 622 nm are respectively achieved.