Advanced search
Start date
Betweenand
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

Full text
Author(s):
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]
Total Authors: 10
Affiliation:
[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
Total Affiliations: 7
Document type: Journal article
Source: CrystEngComm; v. 17, n. 7, p. 1654-1666, 2015.
Web of Science Citations: 34
Abstract

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)

FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC