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Title: A new member of “114” family Ca{sub 1−x}Eu{sub x}BaZn{sub 2+x}Ga{sub 2−x}O{sub 7} (x≤0.24): Structure and luminescence

New “114” oxides Ca{sub 1−x}Eu{sub x}BaZn{sub 2+x}Ga{sub 2−x}O{sub 7} (x≤0.24) were synthesized by solid state reaction. Rietveld refinements were performed on high quality powder XRD data in the space group P6{sub 3}mc. Zn{sup 2+} and Ga{sup 3+} co-occupy T1 and T2 positions, which are both in tetrahedral coordinated environment. Comparing the host compound, O3 moves towards T2 cation as much as 0.08 Å when x=0.24. It is the most observable structural change during the substitution. By comparing the structures of CaBaZn{sub 2}Ga{sub 2}O{sub 7} (P6{sub 3}mc) and CaBaCo{sub 4}O{sub 7} (Pbn2{sub 1}), we find that smaller cations in tetrahedral sites would lead to a lower symmetry in “114” oxides. Luminescent spectra show the noncentrosymmetric coordination of Eu{sup 3+}, and the f–f excitations are comparable to CT-excitation. No concentration quenching was observed up to x=0.24. The optical band gaps were estimated to be 3.8 eV for Ca{sub 1−x}Eu{sub x}BaZn{sub 2+x}Ga{sub 2−x}O{sub 7} (x=0, 0.16). - Graphical abstract: Reitveld refinements show Ca{sub 1−x}Eu{sub x}BaZn{sub 2+x}Ga{sub 2−x}O{sub 7} all crystallize in P6{sub 3}mc. By Eu{sup 3+}-doping, O3 show the most obvious movement (∼0.08 Å) along the c-axis. Display Omitted - Highlights: • Ca{sub 1−x}Eu{sub x}BaZn{sub 2+x}Ga{sub 2−x}O{sub 7} (x≤0.24) solid solutions were synthesizedmore » in air. • Rietveld refinements of high quality powder XRD show good convergences. • Ca{sub 1−x}Eu{sub x}BaZn{sub 2+x}Ga{sub 2−x}O{sub 7} all crystallize in the space group P6{sub 3}mc. • Luminescent spectra of Eu{sup 3+} show no quenching effect up to x=0.24. • Optical band gaps for CaBaZn{sub 2}Ga{sub 2}O{sub 7} are estimated to be 3.8 eV.« less
Authors:
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Publication Date:
OSTI Identifier:
22274151
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 207; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATIONS; EUROPIUM IONS; EXCITATION; GALLIUM IONS; HEXAGONAL LATTICES; LUMINESCENCE; ORTHORHOMBIC LATTICES; POWDERS; QUENCHING; SOLIDS; SOLUTIONS; SPACE GROUPS; SPECTRA; X-RAY DIFFRACTION; ZINC IONS