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Title: Synthesis and Thermally Stimulated Luminescence of Polycrystalline Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7}

Abstract

Specific features of the solid-phase synthesis of Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7} (x 0-0.15) in air are studied. The photo- and thermally stimulated luminescence of Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7} is investigated in the range of Eu content 0.01 < x < 0.15. The main energy parameters of traps are determined. It is shown that the peak of thermally stimulated luminescence at T = 380 K can be related to the decomposition and radiative relaxation of the [Eu{sup 3+}{sub Sr{sup 2}{sup +}} F{sup +} center] pair.

Authors:
; ; ;  [1]
  1. Institute for Single Crystals, National Academy of Sciences of Ukraine, pr. Lenina 60, Kharkov, 61001 (Ukraine)
Publication Date:
OSTI Identifier:
20719765
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 50; Journal Issue: 7; Other Information: Translated from Kristallografiya, ISSN 0023-4761, ; DOI: 10.1134/1.2133990; (c) 2005 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); TN:
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BORATES; DECOMPOSITION; EUROPIUM COMPOUNDS; EUROPIUM IONS; F CENTERS; PHOTOLUMINESCENCE; POLYCRYSTALS; POWDERS; STRONTIUM COMPOUNDS; SYNTHESIS; THERMOLUMINESCENCE

Citation Formats

Dubovik, M.F., Korshikova, T.I., Parkhomenko, S.V., and Tolmachev, A.V. Synthesis and Thermally Stimulated Luminescence of Polycrystalline Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7}. United States: N. p., 2005. Web. doi:10.1134/1.2133990.
Dubovik, M.F., Korshikova, T.I., Parkhomenko, S.V., & Tolmachev, A.V. Synthesis and Thermally Stimulated Luminescence of Polycrystalline Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7}. United States. doi:10.1134/1.2133990.
Dubovik, M.F., Korshikova, T.I., Parkhomenko, S.V., and Tolmachev, A.V. Thu . "Synthesis and Thermally Stimulated Luminescence of Polycrystalline Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7}". United States. doi:10.1134/1.2133990.
@article{osti_20719765,
title = {Synthesis and Thermally Stimulated Luminescence of Polycrystalline Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7}},
author = {Dubovik, M.F. and Korshikova, T.I. and Parkhomenko, S.V. and Tolmachev, A.V.},
abstractNote = {Specific features of the solid-phase synthesis of Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7} (x 0-0.15) in air are studied. The photo- and thermally stimulated luminescence of Sr{sub 1-x}Eu{sub x}B{sub 4}O{sub 7} is investigated in the range of Eu content 0.01 < x < 0.15. The main energy parameters of traps are determined. It is shown that the peak of thermally stimulated luminescence at T = 380 K can be related to the decomposition and radiative relaxation of the [Eu{sup 3+}{sub Sr{sup 2}{sup +}} F{sup +} center] pair.},
doi = {10.1134/1.2133990},
journal = {Crystallography Reports},
number = 7,
volume = 50,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O with the Eu{sup 3+}-doping upper limit of 40 atom% were synthesized hydrothermally. Thereafter, thermal treatments at 710 °C were applied to obtain β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9}. The solid solution range is even narrower, i.e. 0≤x≤0.15, due to the mismatch between La{sup 3+} and Eu{sup 3+}. The host borate system shows a typical concentration quenching effect at x=0.20 under CT excitation, and this is postponed to x=0.30 under the f−f excitation. β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} shows a very intense absorption of charge transfer, and gives strong red emissions at 615 nm withmore » large R/O ratios (1.9–2.4). The saturation effect appears at x=0.11, which is probably due to the lattice distortion. Eu{sup 3+} luminescence was applied as the structural probe to study the local coordination environment change during the dehydration and re-crystallization processes of La{sub 0.93}Eu{sub 0.07}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O. - Highlights: • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O (0≤x≤0.40) were prepared by hydrothermal method. • The Eu{sup 3+}-doping limit in β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} is 15 atom% proved by powder XRD. • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O show relatively weaker red emissions. • β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} shows an intense CT absorption together with strong red emissions. • Eu{sup 3+} luminescence was studied when annealing La{sub 0.93}Eu{sub 0.07}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O.« less
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  • The role of B{sub 2}O{sub 3} in realizing the long phosphorescence of Eu(II)+Dy(III) doped strontium aluminates has been investigated. IR and solid state {sup 27}Al MAS NMR spectra show the incorporation of boron as BO{sub 4} in the AlO{sub 4} framework of SrAl{sub 2}O{sub 4} and Sr{sub 4}Al{sub 14}O{sub 25}. Phosphor, made free of glassy phases by washing with hot acetic acid+glycerol, did not show any photoconductivity under UV irradiation, indicating that the mechanism involving hole conduction in valence band is untenable for long phosphorescence. EPR studies confirm the presence of both electron and hole trap centers. Dy{sup 3+} formsmore » substitutional defect complex with borate; [Dy-BO{sub 4}-V{sub Sr}]{sup 2-}, and acts as a hole trap center. The electron centers are formed by the oxygen vacancies associated with BO{sub 3}{sup 3-}, i.e. [BO{sub 3}-V{sub O}]{sup 3-}. Under indigo light or near UV irradiation, the photoinduced electron centers are formed as [BO{sub 3}-V{sub O}(e')]{sup 4-}. The holes are released from [Dy-BO{sub 4}-V{sub Sr}(h{center_dot})]{sup 1-} under thermal excitation at room temperature. The recombination of electrons with holes releases energy which is expended to excite Eu{sup 2+} to induce long phosphorescence.« less
  • New oxysilicates with the general formula ALa{sub 3}Bi(SiO{sub 4}){sub 3}O and ALa{sub 2}Bi{sub 2}(SiO{sub 4}){sub 3}O [A=Ca, Sr and Ba] are synthesized and characterized. Powder X-ray diffraction of these silicates show that they are isostructural with BiCa{sub 4}(VO{sub 4}){sub 3}O which has an apatite-related structure. Eu{sup 3+} luminescence in the newly synthesized oxysilicates show broad emission lines due to disorder of cations. The relatively high intense magnetic dipole transition {sup 5}D{sub 0}->{sup 7}F{sub 1} points to a more symmetric environment. The photoluminescence results confirm that the compounds have apatite-related crystal structure.