Hydrothermal synthesis and optical properties of hexagonal tungsten oxide nanocrystals assisted by ammonium tartrate

Pang, Hua-Feng, Xiang, Xia, Li, Zhi-Jie, Fu, Yong Qing and Zu, Xiao-Tao (2011) Hydrothermal synthesis and optical properties of hexagonal tungsten oxide nanocrystals assisted by ammonium tartrate. physica status solidi (a), 209 (3). pp. 537-544. ISSN 1862 6300

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Official URL: http://dx.doi.org/10.1002/pssa.201127456

Abstract

Crystals of hexagonal tungsten oxides (hex-WO3) have been synthesized using hydrothermal method at 150 °C, assisted by the capping reagent of ammonium tartrate (AT). The XRD and EDX results reveal that the lattice distortion exists in all the samples, possibly due to the defects and the intercalation of the residual sodium ions. Different crystal shapes including plate-like, urchin-like, and particle structures were obtained by varying concentration of AT and pH values in the precursor solution. Beside the absorption action of the equation image and Na+ ions, the capping effect can be reinforced by the hydrogen bonding from the tartrate groups in the crystallization process. The bandgap energies were modulated by the size of the nanostructured hex-WO3 crystals due to quantum confinement effect, which increases from 2.74 to 3.04 eV. Based on the analysis of the photoluminescence and X-ray photoelectron spectroscopy, the enhancement of the blue emission of the nanocrystals is assigned as a result of a complex of the local intercalation of the residual sodium ions and the oxygen vacancies or defects.

Item Type: Article
Uncontrolled Keywords: hydrothermal synthesis, nanocrystals, photoluminescence, tungsten oxides
Subjects: F200 Materials Science
Department: Faculties > Engineering and Environment > Physics and Electrical Engineering
Depositing User: Becky Skoyles
Date Deposited: 23 Mar 2015 11:25
Last Modified: 10 Aug 2015 11:18
URI: http://nrl.northumbria.ac.uk/id/eprint/21689

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