Novel Route to WO_x Nanorods and WS₂ Nanotubes from WS₂ Inorganic Fullerenes

Abstract

WO(x) (2 < x < 3) and WS(2) nanostructures have been widely praised due to applications as catalysts, solid lubricants, field emitters, and optical components. Many methods have been developed to fabricate these nanomaterials; however, most attention was focused on the same dimensional transformation from WO(x) nanoparticles or nanorods to WS(2) nanoparticles or nanotubes. In a solid-vapor reaction, by simply controlling the quantity of water vapor and reaction temperature, we have realized the transformation from quasi-zero-dimensional WS(2) nanoparticles to one-dimensional W(18)O(49) nanorods, and subsequent sulfuration reactions have further converted these W(18)O(49) nanorods into WS(2) nanotubes. The reaction temperature, quantity of water vapor, and pretreatment of the WS(2) nanoparticle precursors are important process parameters for long, thin, and homogeneous W(18)O(49) nanorods growth. The morphologies, crystal structures, and circling transformation mechanisms of sulfide-oxide-sulfide are discussed, and the photoluminescence properties of the resulting nanorods are investigated using a Xe lamp under an excitation of 270 nm.

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

“…for their spray deposited nano crystalline WO 3 thin films. The blue emission at 418 nm [34,37,38] and blue green emission at 488 nm [38,39] were also close to the reported results. The blue green and blue emission peaks were more intense than the near UV emission and this kind of emissions were already reported [35].…”

Molten-salt synthesis of tungsten oxide nanotubes: Morphological and gas sensitivity

“…In our work, the blue emission peak locals at 420 nm (2.60 eV) which is in accordance with the WO 3 energy gap of 2.4-2.8 eV. But the wavelength measured in this work is shorter than that reported [2,8] , which may be due to the size-effect of the nano-materials. Figure 5 shows the PL property of the nanotubes, the big unsymmetrical tail is observed, and the existence of emission peak at long wavelength maybe originates from the presence of oxygen vacancies defects or K impurity.…”

“…Li et al [8] studied the PL properties of WO 3 nanorods, and found the emission peak at 438 nm. In our work, the blue emission peak locals at 420 nm (2.60 eV) which is in accordance with the WO 3 energy gap of 2.4-2.8 eV.…”

Effect of annealing on microstructure and NO2-sensing properties of tungsten oxide nanowires synthesized by solvothermal method

“…Among various metal oxide semiconductors, tungsten oxide (WO 3−x ), which is a wide band-gap n-type semiconductor, has been considered as a promising sensing material for detection of toxic gases [11,12]. Recent studies about onedimensional tungsten oxide nanostructures like W 18 O 49 nanowires and WO 3 nanotubes have clearly demonstrated the good prospects of tungsten oxide nanostructures in toxic and hazardous gas detection [13][14][15].…”