Syntheses and luminescence study for 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) and the dehydrated products β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} (0≤x≤0.15)
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 with 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.
- OSTI ID:
- 22584067
- Journal Information:
- Journal of Solid State Chemistry, Vol. 237; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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