Controllable synthesis of W18O49 nanowire arrays and their application in electrochromic devices

Abstract

Tungsten oxide nanowire arrays as effective electrochromic working electrodes were fabricated on seed-free FTO glass through a facile solvothermal process. Polyethylene glycol was used as the structure-directing agent to control the crystal growth because of selective absorption on the facet of tungsten oxide crystals. Phase identification and growth mechanism of monoclinic W 18 O 49 nanowire arrays are also extensively discussed. Uniform transparent W 18 O 49 nanowire arrays film exhibits remarkable performance of electrochromic properties, which include high contrast (49.64 % at 632.8 nm), high electrochromic stability ([3000 CV cycles), and fast coloration/bleaching response (t c * 7.9 s, t b * 1.4 s). These properties of the W 18 O 49 nanowire arrays film endow its promising practical applications in large-area smart windows.

Large Area Co-Assembly of Nanowires for Flexible Transparent Smart Windows

“…For instance, we fabricated a flexible solid electrochromic device using the electrochromic films for the applications in portable electrochromic glasses and smart windows. Figure a shows the structural schematic diagram of the solid electrochromic device of which the Ag/W 18 O 49 NW film and ITO-PET film were used as the work and counter electrode, 0.5 M LiClO 4 /PC (propylene carbonate) with 10 wt % PMMA (poly­(methyl methacrylate)) as stiffer was used as solid electrolyte. , The flexibility of the representative electrochromic windows at bleached and colored states is shown in Figure b,c and it still maintains the functionality of quick response to electric signal even at bending state. A model of electrochromic eyeglass was assembled as shown in Figure d and the colored state can be obviously observed when a negative voltage is applied.…”

Advanced developments in nonstoichiometric tungsten oxides for electrochromic applications

“…The sample calcined upto 400 ºC was stable and no phase-change was observed, however, increasing the calcination temperature >400 ºC, phase conversion to monoclinic WO 3 took place. Lu et al284 grown a vertical nanowire array on FTO glass for the…”

Synthesis of tungsten oxo fluoroalkoxide complexes WO(OR)3L as precursors for growth of WOx nanomaterials by aerosol-assisted chemical vapor deposition

“…Nanosheets and polycrystalline films of W 18 O 49 have been reported, however they are less common due to the preferential growth along the [010] direction[59,60]. It has been suggested that high oxygen vacancies along the (010) plane of W 18 O 49 play a role in this anisotropic growth[24,61,62].…”