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Photoluminescence properties of an orange-red LaSr2AlO5:Sm3+ phosphor prepared by the Pechini-type sol-gel process
LaSr2AlO5:Sm3+ phosphors were synthesized by the Pechini-type sol-gel process. The X-ray diffraction pattern revealed that a pure LaSr2AlO5 phase was obtained with a sintering temperature of 1200 °C. Microstructure characterization showed that the particles were spherical in shape with a mean size o...
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Published in: | Journal of rare earths 2015-09, Vol.33 (9), p.954-960 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
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Online Access: | Get full text |
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Summary: | LaSr2AlO5:Sm3+ phosphors were synthesized by the Pechini-type sol-gel process. The X-ray diffraction pattern revealed that a pure LaSr2AlO5 phase was obtained with a sintering temperature of 1200 °C. Microstructure characterization showed that the particles were spherical in shape with a mean size of 2.93 µm. Being a candidate orange/red emitting phosphor for orange and white light emitting diodes, LaSr2AlO5:Sm3+ could be effectively excited by both near-ultraviolet (NUV) and blue lights with typical f-f transitions of Sm3+ ions. The most intense emission corresponding to 4G5/2→6H7/2 (604 nm) could be achieved at the same Sm3+ concentration of 4 mol.%. The chromaticity coordinates of La0.96Sr2AlO5:0.04Sm3+ phosphor under the excitation of 407 and 458 nm were (0.57, 0.43) and (0.59, 0.38), respectively. Further study was carried out using Van Uitert's and Dexter's models. A consistent result was obtained that electric dipole-dipole interaction was dominant for the energy transfer among Sm3+ ions. The critical distance for energy transfer among Sm3+ ions in LaSr2AlO5 was calculated to be ca. 1.843 nm.
PL spectra of the La1–xSr2AlO5:xSm3+ (x=0.005–0.15) phosphors excited at 407 nm (a) and at 458 nm (b) |
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ISSN: | 1002-0721 2509-4963 |
DOI: | 10.1016/S1002-0721(14)60511-1 |