Raman spectra of sol-gel-derived tungsten oxides

Nonaka, Kohei; Takase, Akira; Miyakawa, Kenji

doi:10.1007/bf01910075

Cited by 63 publications

(39 citation statements)

References 18 publications

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“…2.1 Vibrational and structural analysis Raman and XRD analysis of tungsten trioxide have been reported numerous times [22][23][24][25][26], and despite the simple stoichiometry, the structure is very complex [27][28][29]. Raman spectroscopy was done on two areas of the sample as denoted by spot 1 and spot 2 of the Raman image shown in the inset of Figure 2.…”

Section: Resultsmentioning

confidence: 99%

Electrical and optical properties of mixed phase tungsten trioxide films grown by laser pyrolysis

Govender

Mwakikunga

Machatine

et al. 2014

Phys. Status Solidi C

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Laser pyrolysis is a synthesis method used to produce thin films and nanomaterials of high quality and purity, by intersecting a laser beam with a chemical precursor. We have chosen laser pyrolysis to synthesize tungsten trioxide starting with tungsten ethoxide precursor. The film had a thickness that varied from 205 nm to 1 µm. Xray diffraction and Raman spectroscopy confirmed the presence of a mixture of hexagonal and tetragonal phase WO 3 in the synthesized film, and it was clear that annealing greatly influenced the phases and types of structures formed. I-V curves of the films showed n-type semiconducting behaviour, but the mixed phase appeared to cause a similar behaviour of dopants in a semiconductor. The refractive index decreased with increasing wavelength and gave values of up to 21 at low wavelengths. The average optical band gap was found to 3.6 eV from UV/Vis spectroscopy. Scanning Electron Microscopy (SEM) showed a mixture of nano-and microstructures and shapes formed after annealing. One of the grown nanostructures was nanorods, this isolated using FIB for possible applications such as an active sensing medium in gas sensors.

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Section: Resultsmentioning

confidence: 99%

Electrical and optical properties of mixed phase tungsten trioxide films grown by laser pyrolysis

Govender

Mwakikunga

Machatine

et al. 2014

Phys. Status Solidi C

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“…It was accompanied by the appearance of a broad feature centered around 960 cm À1 and of two new bands at 220 and 380 cm À1 . They are all attributable to the hydrated form of WO 3 [27,28], thus its formation was postulated to take place upon insertion of protons. In the present study, we observed only a very weak band around 220 cm À1 , which may be indicative of WO 3 .…”

Section: Raman Studiesmentioning

confidence: 98%

The core–shell nature of nanostructured WO3 photoelectrodes demonstrated in spectroelectrochemical studies

Królikowska

Barczuk

Jurczakowski

et al. 2011

Journal of Electroanalytical Chemistry

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“…5b. The bending modes of WO 3 are predominantly seen between 600 and 900 cm −1 , while the stretching modes can be observed between 200 and 500 cm −1 [42]. Distinctive band detected at 802 cm −1 has been assigned to the symmetric stretching mode of terminal (W 6+ =O) groups which may also be vibrationally coupled [43].…”

Section: Resultsmentioning

confidence: 96%

Mechanically exfoliated ultra-thin WO3 nanostructures: study of their enhanced electrical properties

Zhuiykov

Kats

2014

Ionics

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Ultra-thin orthorhombic β-WO 3 nanoflakes were prepared by two-step sol-gel-exfoliation method and sintered at 550 and 650°C, respectively. Their morphology and electrical properties were investigated by the following material characterisation techniques: energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy. CSFS-AFM analysis exhibited good correlation between the topography of the developed nanostructures and various features of WO 3 nanoflakes. It was found that β-WO 3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, microstructured and nanostructured WO 3 synthesized at alternative temperatures.

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Raman spectra of sol-gel-derived tungsten oxides

Cited by 63 publications

References 18 publications

Electrical and optical properties of mixed phase tungsten trioxide films grown by laser pyrolysis

Electrical and optical properties of mixed phase tungsten trioxide films grown by laser pyrolysis

The core–shell nature of nanostructured WO3 photoelectrodes demonstrated in spectroelectrochemical studies

Mechanically exfoliated ultra-thin WO3 nanostructures: study of their enhanced electrical properties

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