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Intense ultraviolet emission from needle-like WO3 nanostructures synthesized by noncatalytic thermal evaporation.

Park S, Kim H, Jin C, Lee C - Nanoscale Res Lett (2011)

Bottom Line: Photoluminescence measurements showed that needle-like tungsten oxide nanostructures synthesized at 590°C to 750°C by the thermal evaporation of WO3 nanopowders without the use of a catalyst had an intense near-ultraviolet (NUV) emission band that was different from that of the tungsten oxide nanostructures obtained in other temperature ranges.The intense NUV emission might be due to the localized states associated with oxygen vacancies and surface states.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Materials Science and Engineering, Inha University, 253 Yonghyeon-dong, Nam-gu, Incheon 402-751, Republic of Korea. cmlee@inha.ac.kr.

ABSTRACT
Photoluminescence measurements showed that needle-like tungsten oxide nanostructures synthesized at 590°C to 750°C by the thermal evaporation of WO3 nanopowders without the use of a catalyst had an intense near-ultraviolet (NUV) emission band that was different from that of the tungsten oxide nanostructures obtained in other temperature ranges. The intense NUV emission might be due to the localized states associated with oxygen vacancies and surface states.

No MeSH data available.


PL spectra of the nanostructures. PL spectra of the tungsten oxide nanostructures grown in the different substrate temperature zones.
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Figure 3: PL spectra of the nanostructures. PL spectra of the tungsten oxide nanostructures grown in the different substrate temperature zones.

Mentions: Figure 3 shows the PL spectra of the nanostructures synthesized at five different substrate temperature zones. A relatively strong broad blue emission band centered at approximately 475 nm, and several shoulders exist in the spectrum of the nanostructures synthesized in zone 1. This blue emission might be attributed to the band-to-band emission, as suggested by Niederberger et al. [7] and Luo et al. [8], because the photon energy 2.61 eV corresponding to the wavelength of the blue emission falls in the range of the indirect energy gap of tungsten oxide corresponding to 475 nm. This is in good agreement with previous reports. Chang et al. [11] observed a strong blue emission peak at approximately 470 nm in the PL spectrum of nitrogen-doped tungsten oxide nanowires synthesized by reducing the tungsten oxide source with NH3 gas on a Si wafer. Luo et al. [8] also reported strong blue emission band centered at 467 nm from tungsten oxide nanowire networks. In contrast, a sharp strong NUV emission band at 390 nm and a broad weak blue emission band centered approximately at 475 nm from the needle-like nanostructures grown in zone 2 were observed in this study. The strong NUV emission from our tungsten oxide nanowires synthesized in zone 2 can be explained by a combination of the following two sources:


Intense ultraviolet emission from needle-like WO3 nanostructures synthesized by noncatalytic thermal evaporation.

Park S, Kim H, Jin C, Lee C - Nanoscale Res Lett (2011)

PL spectra of the nanostructures. PL spectra of the tungsten oxide nanostructures grown in the different substrate temperature zones.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211871&req=5

Figure 3: PL spectra of the nanostructures. PL spectra of the tungsten oxide nanostructures grown in the different substrate temperature zones.
Mentions: Figure 3 shows the PL spectra of the nanostructures synthesized at five different substrate temperature zones. A relatively strong broad blue emission band centered at approximately 475 nm, and several shoulders exist in the spectrum of the nanostructures synthesized in zone 1. This blue emission might be attributed to the band-to-band emission, as suggested by Niederberger et al. [7] and Luo et al. [8], because the photon energy 2.61 eV corresponding to the wavelength of the blue emission falls in the range of the indirect energy gap of tungsten oxide corresponding to 475 nm. This is in good agreement with previous reports. Chang et al. [11] observed a strong blue emission peak at approximately 470 nm in the PL spectrum of nitrogen-doped tungsten oxide nanowires synthesized by reducing the tungsten oxide source with NH3 gas on a Si wafer. Luo et al. [8] also reported strong blue emission band centered at 467 nm from tungsten oxide nanowire networks. In contrast, a sharp strong NUV emission band at 390 nm and a broad weak blue emission band centered approximately at 475 nm from the needle-like nanostructures grown in zone 2 were observed in this study. The strong NUV emission from our tungsten oxide nanowires synthesized in zone 2 can be explained by a combination of the following two sources:

Bottom Line: Photoluminescence measurements showed that needle-like tungsten oxide nanostructures synthesized at 590°C to 750°C by the thermal evaporation of WO3 nanopowders without the use of a catalyst had an intense near-ultraviolet (NUV) emission band that was different from that of the tungsten oxide nanostructures obtained in other temperature ranges.The intense NUV emission might be due to the localized states associated with oxygen vacancies and surface states.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Materials Science and Engineering, Inha University, 253 Yonghyeon-dong, Nam-gu, Incheon 402-751, Republic of Korea. cmlee@inha.ac.kr.

ABSTRACT
Photoluminescence measurements showed that needle-like tungsten oxide nanostructures synthesized at 590°C to 750°C by the thermal evaporation of WO3 nanopowders without the use of a catalyst had an intense near-ultraviolet (NUV) emission band that was different from that of the tungsten oxide nanostructures obtained in other temperature ranges. The intense NUV emission might be due to the localized states associated with oxygen vacancies and surface states.

No MeSH data available.