Flexible electrochromic tungsten/iron mixed oxide films synthesized by an atmospheric pressure plasma jet.

Abstract Flexible electrochromic organo-tungsten-iron oxide (WFe x O y C z) films are rapidly deposited onto flexible (60 Ω/□ polyethylene terephthalate/indium tin oxide; PET/ITO) substrates by a low temperature-atmospheric pressure-plasma polymerization method with an atmospheric pressure plasma jet (APPJ) for a short exposed duration of 48 s. The precursor vapors of tungsten hexacarbonyl [W(CO) 6 ] and biscyclopentadienyl iron [ferrocene; Fe(C 5 H 5) 2 ] are mixed with O 2 gases at various gas flow rates, injected into air plasma jet and sprayed onto PET/ITO substrates at room temperature (~23 °C) and at atmospheric pressure (1.013 × 105 Pa). Flexible electrochromic WFe x O y C z films are synthesized with a specific addition of oxygen gases with superior lithium electrochromic properties as demonstrated by a potential sweep alternating between −1 V and 2 V at a scan rate of 40 mV/s in a 1 M LiClO 4 -propylene carbonate electrolyte. With amorphous WFe x O y C z films produced with an APPJ by adding oxygen gases at a specific flow rate of 0.5 sccm, a high value in oxygen deficiency up to 0.189 allows more Li+ ions to intercalate into and deintercalate out of the film. Significant coloration and bleaching are proven by the high values in optical transmittance modulation (Δ T) of up to 70.3%, optical density (Δ OD) up to 0.77 and color efficiency (η) up to 61.3 cm2/C, at a wavelength of 800 nm, respectively. Highlights • Rapid deposition of flexible WFe x O y C z film using atmospheric pressure plasma jet. • Enhanced electrochromic performance of WFe x O y C z films by addition oxygen gases. • Notable light modulation on WFe x O y C z films is achieved. • Porous surfaces of WFe x O y C z films offer reversibly coloration and bleaching. [ABSTRACT FROM AUTHOR]