Solid state electrochromic devices of plasma modified WO3 hybrids

Abstract

Electrochromic (EC) properties of tungsten trioxide (WO3) was improved with preparing hybrids of tungsten trioxide-titanium dioxide (WO3-TiO2) and tungsten trioxide-poly(3,4-ethylenedioxythiophene) (WO3-PEDOT) by a rotating capacitively coupled radio frequency (rf 13.56 MHz) plasma reactor. Energy-dispersive X-ray spectroscopy mapping results indicated that TiO2 and PEDOT were coated homogeneously onto the surface of the WO3 powders. Thin films of hybrid powders have been prepared by the physical vapor deposition method of the electron beam evaporation technique. Redox potentials, optical contrast at 700 nm, and durability during 2000 cycles of EC devices were investigated, comparatively. Hybrids of WO3 indicated excellent coloration efficiency (cm2 C-1) and switching speed values compared with untreated WO3. The coloration efficiency values were found to be 85.88 and 41.61 cm2 C-1 of WO3-TiO2 and WO3-PEDOT, respectively. The switching speed of WO3 (13.3 s, from bleached state to colored state) increased to 1.4 s for WO3-TiO2.