Synthesis, Characterization And Application Of One - Dimensional Tungsten Oxide Nanowires

Tungsten oxide(WO_3-x) with varied valence have been widely used in electrochromic‘‘smart’’ windows, gas sensing and optoelectronic devices due to its excellent physical and chemical properties, especially chromogenic phenomena. This paper first reviews the characteristics of the crystal structure, the electrochromic and gasochromic properties.Furthermore discusses some corresponding issues of the chromogenic, device structure model incorporates the results of our group. At last, the following three areas of research are studied, some interesting results are obtained in the process.1) Three different morphologies tungsten oxide film were obtained by studied the effect of oxygen concentration on the morphology, which are nanorods, nanowires and three-dimensional network. Three-dimensional network structure was analyzed through change growth time and HRTEM results. The growth process of complex 3D-WO₃ nanowires network were discussed in detail, which will help to achieve more three-dimensional metal oxide nano-wire network.2) Compared three different topographies of tungsten oxide gasochromic phenomenon,three-dimensional network structure have the deepest contrast color and its response time is approaching 0.1 s, but the faster recovery rate is amorphous film. Furthermore,studied the tungsten oxide nanowire film applications in gas sensors, and the film can probe the concentration of hydrogen sensitivity up to 50 ppm in the air environment.3) Rare earth ions were successfully doped into tungsten oxide nanowires. The characteristic emission peaks belongs to Eu³⁺ were detected, and as the temperature increases, the rare earth ions were in the lower environmental symmetry of the crystal field. In situ Temperature Raman spectroscopy was tested to the Eu@WO₃ sample. As the temperature changes, the structure of the Raman peaks and Eu³⁺ fluorescence spectrum peak variation reversible, the emerging broad peak belongs to defects luminescence of the semiconductor material luminescence changes irreversible.