Flame Synthesized Nanostructured WO3 Thin Films for Photoelectrochemical Water Splitting

J-R Ding, K-S Kim
Kangwon Natonal University, KR

Keywords: tungsten oxide thin film, flame synthesis, water splitting


Tungsten oxide has been considered as a promising photoanode material for photoelectrochemcial water-splitting techonologies due to its ralatively favorable band gap position and good charge transport property and stablity in aqueous solution. Typically, 1-dimentional structure such as nanotube is of great interest because of its axial long-range length for enhancing light absorption as well as electrons transport and radial short length for holes diffusion to WO3/electrolyte inferface. However, nearly cubic WO3 crystal tends to grow as an isotropic 3-D structure, instead, the sub-stochiometric W18O49 (WO2.72) has inrinsically anisotropic growth property. By taking advantage of that, 1-D WO2.72 were synthesized in fuel-rich premixed flame using tunsten wire as precursor by aerosol flame deposition process followed by air annealing to convert WO2.72 to WO3. WO3 thin films with nanotube, nanoflower and nanobouquet aligned on FTO conductive glass were obtained. We investigated the effects of the various process parameters, such as metal wire position between substrate and flame burner, deposition height, substrate temperature and deposition time on the resultant morphology and thickness of WO3 thin films, respectively. The structural properties were characterized by Scanning Electron Microscopy and X-ray diffraction and the photoelectrochemical properties were tested by IPCE measurement system.