Publication Date:
2017-12-29
Description:
The electronic, structural and optical properties of two red phosphors, Rb 2 HfF 6 :Mn 4+ and Cs 2 HfF 6 :Mn 4+ , are evaluated using the first-principles and crystal field theory methods. The calculated trigonal splitting of the Mn 4+ orbital triplets perfectly matches the experimental excitation spectra. The structural and electronic properties of the mixed compound RbCsHfF 6 are also studied theoretically. In the mixed compound, the inversion center symmetry around the Hf site is removed. This symmetry lowering may result in an increase in the Mn 4+ 2 E 4 A 2 zero phonon line (ZPL) intensity, which is very weak in the two end members. This finding may be of interest for increasing the phosphor luminosity. It is believed that such a mechanism of local site symmetry lowering by preparing solid solutions may be used for other systems as well, to gain ZPL intensity and perhaps to minimize thermal losses, eventually leading to improved phosphor materials. This article is protected by copyright. All rights reserved.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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