Temperature and exposure time-dependent scintillation of Eu(III) polyoxometalate under X-ray excitation

Author(s)

de Souza Oliveira, Higor Henrique ^{[1, 2]} ; Cebim, Marco Aurelio ^[1] ; Davolos, Marian Rosaly ^[1]

Affiliation

^[1] Univ Estadual Paulista UNESP, Inst Quim, Araraquara, SP - Brazil

^[2] Inst Fed Educ Ciencia & Tecnol Sao Paulo IFSP, Matao, SP - Brazil

• Document type: Journal article
• Source: Journal of Luminescence; v. 203, p. 230-233, NOV 2018.
• Web of Science Citations: 1

Abstract

Sodium decatungstoeuropate, Na-9{[}Eu(W5O18)(2)]center dot 14H(2)O, is a promising material to convert X-ray into visible light. In this work, temperature and exposure time-dependent scintillation of the Na-9{[}Eu(W5O18)(2)]center dot 14H(2)O sample under X-ray excitation were evaluated. Light emission intensity decreases along with X-ray exposure time, probably due to electronic defects at (W5O18)(6-) groups, leading to a lower efficiency of the LMCT (O -> W) process, which is determinant in the scintillation mechanism of this material. After X-ray exposition, there is a partial recovery of the initial emission intensity, indicating that defects created are reversible. With temperature increasing, changes in the emission spectra evidence the decreasing of the local symmetry around the Eu3+ ions, caused by reticular vibration and dehydration process. The luminescence intensity dependence with temperature suggests the possibility to use this material as molecular thermometer in two different temperatures ranges. (AU)