Structure evolution and tunable luminescence of (Sr(0.98-m)Ba(m)Eu(0.02))(2)Ca(Mo(1-n)W(n))O(6) phosphor with ultraviolet excitation for white LEDs

Double perovskite (Sr(0.98-m)Ba(m)Eu(0.02))(2)Ca(Mo(1-n)W(n))O(6) phosphors were successfully synthesized by an improved citrate-EDTA complexing method. The structure evolution and the resulting luminescence variation were systematically investigated by X-ray diffraction with Rietveld structure refi...

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Bibliographic Details
Published in:Journal of alloys and compounds 2013-05, Vol.558, p.229-235
Main Authors: Zhang, Le, Han, Pengde, Han, Yong, Lu, Zhou, Yang, Hao, Wang, Lixi, Zhang, Qitu
Format: Article
Language:English
Subjects:
Crystal lattices
Evolution
Excitation
Luminescence
Phosphors
Spectra
Symmetry
Ultraviolet
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Summary:Double perovskite (Sr(0.98-m)Ba(m)Eu(0.02))(2)Ca(Mo(1-n)W(n))O(6) phosphors were successfully synthesized by an improved citrate-EDTA complexing method. The structure evolution and the resulting luminescence variation were systematically investigated by X-ray diffraction with Rietveld structure refinement, Fourier transform infrared spectra, Raman spectra, diffuse reflection spectra and photoluminescence spectra. The increased crystal symmetry and increased lattice parameters were observed from(Sr(0.98-m)Ba(m)Eu(0.02))(2)Ca(Mo(1-n)W(n))O(6) phosphors. These series of phosphors could be effectively excited by near ultraviolet light and emitted a dominant 594 nm ((5)D(0)-(7)F(1)). The hypersensitive ((5)D(0)-(7)F(2)) transition (615 nm) varied with the changed structure symmetry. The CIE chromaticity coordinates were tuned from (0.642, 0.348) to (0.601, 0.389). The luminescence intensity of W6+ substituted powders was greatly enhanced by the blue shift of charge transition band of (Mo/W)O(6) with stable emission color. The composition-optimized Sr(2)Ca(Mo(0.5)W(0.5))O(6):Eu phosphor had the highest luminescence intensity and quantum yield comparing to the commercial red phosphors.
ISSN:0925-8388