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Synthesis and luminescence properties of efficient red phosphors SrAl4O7:Mn4+,R+ (R+=Li+, Na+, and K+) for white LEDs.
- Source :
-
Ceramics International . Jun2015:Part A, Vol. 41 Issue 5, p7191-7196. 6p. - Publication Year :
- 2015
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Abstract
- A series of SrAl [4−(4 x )/3] O 7 : x Mn 4+ (0≤ x ≤1.4 mol%) and Sr (1−0.06/2) Al [4−(4×0.008)/3] O 7 :0.008Mn 4+ ,0.06R + (R + =Li + , Na + , and K + ) phosphors are synthesized by a conventional solid-state reaction method in air. The PLE bands peaking at~325, 395, and 470 nm and the strongest PL band peaking at~660 nm are assigned to the 4 A 2 → 4 T 1 transition of Mn 4+ ion and O 2− –Mn 4+ change transfer band, 4 A 2 → 2 T 1 , 4 A 2 → 4 T 2 , and 2 E → 4 A 2 transitions, respectively. The optimum Mn 4+ doping concentration is about 0.8 mol%. Li + , Na + , and K + ions used as charge compensator can improve observably the PL intensity of SrAl 4 O 7 :Mn 4+ phosphor with excitation 325 nm. The fluorescence lifetimes of SrAl [4−(4×0.008)/3] O 7 :0.008Mn 4+ and Sr [1−0.06/2] Al [4−(4×0.008)/3] O 7 :0.008Mn 4+ ,0.06 R + (R + =Li + , Na + , and K + ) are 0.958, 0.97, 1.113 and 0.965 ms, respectively. The luminous mechanism is explained by schematic energy level diagram of Mn 4+ ion. These experiment results indicate that SrAl 4 O 7 :Mn 4+ ,R + (R + =Li + , Na + , and K + ) phosphors can be used as red emitting phosphor candidate for white LEDs based on a UV (~325 nm) and near UV (~395 nm) bands of LEDs chip. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02728842
- Volume :
- 41
- Issue :
- 5
- Database :
- Academic Search Index
- Journal :
- Ceramics International
- Publication Type :
- Academic Journal
- Accession number :
- 102209063
- Full Text :
- https://doi.org/10.1016/j.ceramint.2015.02.047