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Effect of 130 keV pulsed electron irradiation on the efficiency of radiative transitions in Eu-doped glass-ceramics CaSiO3
Effect of 130 keV pulsed electron irradiation on the efficiency of radiative transitions in Eu-doped glass-ceramics CaSiO3
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Fecha
2021
Autores
Gonzales-Lorenzo C.D.
Ananchenko D.V.
Nikiforov S.V.
Kiryakov A.N.
Zatsepin A.F.
Chubaci J.F.D.
Cano N.F.
Ayala-Arenas J.S.
Watanabe S.
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Elsevier B.V.
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Abstracto
Polycrystalline glass-ceramic CaSiO3 doped with Eu3+ ions was obtained by devitrification. The analysis of the photoluminescent characteristics of the obtained glass-ceramic is carried out. It was found that as a result of the devitrification of CaSiO3, two phases are formed, identified as pseudowollastonite (?-CaSiO3) as the dominant phase together with a small percentage of tridymite (SiO2). The UV–Vis optical absorption of Eu3+-doped CaSiO3 was performed using a UV–Vis spectrophotometer. The main objective of this work was to study the effect of the pulsed corpuscular action of electrons accelerated in a field of 130 keV on energy transitions in the Eu3+ ion. It is found that, upon steady-state excitation of the photoluminescent signal in the PLE spectra of unirradiated samples at wavelengths below 300 nm, two broad excitation peaks are displayed, possibly associated with O ? Eu and O ? Si CT transitions. Above 300 nm the characteristic excitation band from 7F0 ground state to 5Hj, 5D4, 5Gj, 5L6, 5D3, and 5D2 states of the Eu3+ ions are shown. It was found that, as a result of exposure to an electron beam in the photoluminescence spectra of europium, a redistribution of the relative intensities of the 5D0 ? 7F2 and 5D0 ? 7F1 transitions occurs. The calculation of the asymmetry ratio of these transitions showed values for an unirradiated sample R21 = 2.06 and irradiated R21 = 2.52, which indicates a decrease in the symmetry of the crystal field around Eu3+ ions after irradiation. Several reasons for the decrease in the relative intensity of the Eu3+ luminescence signal after electron irradiation, caused by the effect of electrization of the material, intrinsic defects of the matrix, and inhomogeneous phase composition, are discussed. © 2021 Elsevier B.V.
Descripción
This work was carried out with partial financial support from Fundaçăo de Amparo à Pesquisa do Estado de Săo Paulo - FAPESP, Brazil (Process number 2014/03085–0 ). To Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq, Brazil , for fellowship to C.D. Gonzales-Lorenzo (Process number 162741/2015–4 ). The authors would like to express our thanks to Dr. H. Loro from the National Engineering University (UNI), Peru, for allowing us to use the appropriate equipment for optical absorption measurements. Besides, C.D. Gonzales-Lorenzo kindly acknowledges the partial financial support from Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica (CONCYTEC) - Banco Mundial , through its executing unit FONDECYT , Peru (Process number 037-2019-FONDECYT-BM-INC.INV.). A.F. Zatsepin and A.N. Kiryakov were supported by the Russian Science Foundation (Grant N° 21-12-00392 ) and also the Russian Foundation for Basic Research-RFBR grants N° 20-42-660012 .
Palabras clave
Pseudowollastonite CaSiO3,
Electron beam irradiation,
Eu3+ photoluminescence,
Glass-ceramics,
Optical material