Structural Evolution and Effect of the Neighboring Cation on the Photoluminescence of Sr(LiAl3 )1-x (SiMg3 )x N4 :Eu2+ Phosphors.
Angew Chem Int Ed Engl
; 58(23): 7767-7772, 2019 Jun 03.
Article
em En
| MEDLINE
| ID: mdl-30957924
ABSTRACT
In this study, a series of Sr(LiAl3 )1-x (SiMg3 )x N4Eu2+ (SLA-SSM) phosphors were synthesized by a solid-solution process. The emission peak maxima of SLA-SSM range from 615â
nm to 680â
nm, which indicates structural differences in these materials. 7 Li solid-state NMR spectroscopy was utilized to distinguish between the Li(1)N4 and Li(2)N4 tetrahedra in SLA-SSM. Differences in the coordination environments of the two Sr sites were found which explain the unexpected luminescent properties. Three discernible morphologies were detected by scanning electron microscopy. Temperature-dependent photoluminescence and decay times were used to understand the diverse environments of europium ions in the two strontium sites Sr1 and Sr2, which also support the NMR analysis. Moreover, X-ray absorption near-edge structure studies reveal that the Eu2+ concentration in SLA-SSM is much higher than that in in SrLiAl3 N4Eu2+ and SrSiMg3 N4Eu2+ phosphors. Finally, an overall mechanism was proposed to explain the how the change in photoluminescence is controlled by the size of the coordinated cation.
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MEDLINE
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2019
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Article