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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Rietveld refinement, cluster modelling, growth mechanism and photoluminescence properties of CaWO4:Eu3+ microcrystals

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Autor(es):
Goncalves, R. F. [1] ; Cavalcante, L. S. [2] ; Nogueira, I. C. [3] ; Longo, E. [4] ; Godinho, M. J. [4, 5] ; Sczancoski, J. C. [4] ; Mastelaro, V. R. [6] ; Pinatti, I. M. [7] ; Rosa, I. L. V. [7] ; Marques, A. P. A. [1]
Número total de Autores: 10
Afiliação do(s) autor(es):
[1] UNIFESP Univ Fed Sao Paulo, BR-09972270 Diadema, SP - Brazil
[2] Univ Estadual Piaui, CCN, Dept Quim, BR-64002150 Teresina, PI - Brazil
[3] PPGEM, IFMA Inst Fed Educ Ciencia & Tecnol Maranhao, Sao Luis, MA - Brazil
[4] Univ Estadual Paulista, LIEC IQ, BR-14801907 Araraquara, SP - Brazil
[5] UFG, CAC, Dept Quim, BR-75704020 Catalao, Go - Brazil
[6] Univ Sao Paulo, IFSC, BR-13560970 Sao Carlos, SP - Brazil
[7] Univ Fed Sao Carlos, CDMF DQ, BR-13565905 Sao Carlos, SP - Brazil
Número total de Afiliações: 7
Tipo de documento: Artigo Científico
Fonte: CrystEngComm; v. 17, n. 7, p. 1654-1666, 2015.
Citações Web of Science: 34
Resumo

CaWO4:Eu3+ microcrystals (with 0, 1, 2 and 4 mol% Eu3+) were synthesized by a co-precipitation (CP) method and grown in a microwave-assisted hydrothermal (MAH) system at 130 degrees C for 30 min. X-ray diffraction (XRD), Rietveld refinement, X-ray absorption near edge spectroscopy (XANES), Fourier-transform Raman (FT-Raman) and Fourier-transform infrared (FT-IR) spectroscopy indicated that all of the microcrystals have a scheelite-type tetragonal structure without deleterious phases. Structural refinement data were employed to model the {[}CaO8], {[}EuO8] and {[}WO4] clusters. XANES spectra confirmed that the presence of deltahedral {[}EuO8] clusters promotes small distortions of neighbouring tetrahedral {[}WO4] clusters in a global tetragonal lattice. Field emission scanning electron microcopy (FE-SEM) images revealed that the replacement of Ca2+ by Eu3+ ions changed the particles' shapes, resulting in the different morphologies of the microcrystals. UV-vis diffuse reflectance spectra indicated a reduction in the optical band gap with the replacement of Ca2+ by Eu3+ ions. The photoluminescence (PL) properties of the Eu3+ ions in CaWO4 were studied as well as the chromaticity coordinates and lifetimes of these compounds. (AU)

Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
Beneficiário:Elson Longo da Silva
Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs