Synthesis, Characterization, Anisotropic Growth and Photoluminescence of BaWO4
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Data
2009-02-01
Autores
Cavalcante, L. S.
Sczancoski, J. C.
Lima, L. F.
Espinosa, J. W. M. [UNESP]
Pizani, P. S.
Varela, José Arana [UNESP]
Longo, Elson [UNESP]
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Amer Chemical Soc
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This paper reports on the synthesis of barium tungstate (BaWO4) powders obtained by the coprecipitation method and processed in a domestic microwave-hydrothermal (MH) at 413 K for different times. These powders were analyzed by X-ray diffraction (XRD), Fourier transform Raman (FT-Raman) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and fieldemission gun scanning electron microscopy (FEG-SEM). XRD patterns showed that the BaWO4 powders present a scheelite-type tetragonal structure and free of secondary phases. FT-Raman spectra proved the evidence of a tetragonal structure due to W-O stretching vibration into the [WO4] tetrahedron groups. FT-IR spectra revealed a strong shoulder on the nu(3) bands in the transmittance spectra of the powders. FEG-SEM micrographs indicated that the powders present an octahedron-like morphology with agglomerated nature and polydisperse particle size distribution. The morphological evolution of BaWO4 powders with the processing time in a MH system was investigated and a possible growth mechanism was proposed. A green photoluminescence (PL) emission at room temperature was verified for the BaWO4 powders when exited by 488 nm wavelength. Finally, a model was proposed to explain this physical property.
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Crystal Growth & Design. Washington: Amer Chemical Soc, v. 9, n. 2, p. 1002-1012, 2009.