Preparation and characterization of tungsten oxynitride nanowires

Abstract

Tungsten oxynitride nanowires were generated by the reaction of ammonia with ultra-thin tungsten oxide nanowires which were themselves prepared by a simple solvo-thermal treatment of tungsten chloride in a cyclohexanol solvent. The resulting tungsten oxynitride nanowires exhibited a high specific surface area of 221 m 2 g 21 , even exceeding that of 151 m 2 g 21 for the bundled and ultra-thin tungsten oxide nanowire precursor. The observed weak, temperature-independent paramagnetism indicates that the tungsten oxynitride nanowires are metallic, but no superconducting transition was observed above 2 K.

Influence of Dopant Concentration on the Electrochromic Properties of Tungsten Oxide Thin Films

“…The near ultraviolet emission at 375 nm giving an energy band gap of 3.3 eV was nearer to the reported values of either 369 nm or 390 nm [34,35]. The emission peak at 375 nm may be attributed to the recombination of free excitons and can be referred to as near band edge emission (NBE) as observed by Mukherjee et al [36].…”

Elastic and electronic properties of hexagonal and cubic polymorphs of tungsten monocarbide WC and mononitride WN from first‐principles calculations

“…These compounds belong to the most promising engineering materials with a wide range of industrial applications [1][2][3][4][5][6][7]. Besides bulk W-C(N) materials, recently much interest was aroused in their nanosized forms, such as nanopowders, nanowires, nanotubes and nanocomposites [7][8][9][10][11][12][13].…”

NH3-treated WO3 as low-cost and efficient counter electrode for dye-sensitized solar cells

“…In the condition of WO 3 , the low-intensity and relatively broad peak at 400.2 eV can be ascribed to the γ-N state caused by chemisorbed nitrogen molecules on the WO 3 surface [19]. In the condition of NH 3 -treated WO 3 , the high-intensity peak at 396.9 eV can be observed, which corresponds to the β-N state and is essentially the atomic N [18,19], demonstrating that nitrogen has been successfully incorporated into the WO 3 .…”

“…The peaks at 35.77 eV (W 4f 7/2 ) and 37.97 eV (W 4f 5/2 ) from WO 3 can be ascribed to the binding energy of high oxidation state of W. In comparison, one additional peak at 33.32 eV (W4f 7/2 ), which is associated with lower oxidation states of W, can be observed from the NH 3 -treated WO 3 sample, indicating the formation of W-N bonds in NH 3 -treated WO 3 as might be expected in tungsten oxynitrides [18]. In addition, the peaks located at 35.37 and 37.47 eV from NH 3 -treated WO 3 are lower compared with those from the pristine WO 3 (35.77 and 37.97 eV), which probably result from the existence of less electronegative atoms into the oxide lattice considering the fact that N has smaller electronegativity (3.04) than O (3.44).…”