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LUMINESCENCE OF Bi3+ and Eu2+ DOUBLE CENTERS DOPED IN CaS HOST
JIA DONG-DONG (贾冬冬), WU BO-QUN (吴伯群), ZHU JING (朱静), L. Lu
Acta Physica Sinica (Overseas Edition), 1999, 8 (11):
813-819.
DOI: 10.1088/1004-423X/8/11/003
In this work, double-center.doped luminescent material CaS:Bi3+, Eu2+ was made via flux NH4Cl by sintering in excess sulfur environment. The sample had a purplish red net luminescent color. Excitation spectra at both red, 650 nm and blue, 487 nrn were taken. The red emission from Eu2+ center was mainly come from the 4f65d1 absorption in the CaS host. The blue emission from the Bi3+ center on the other hand showed no big difference from the singly doped CaS:Bi3+ materials in excitation spectrum. Emission spectra were obtained at excitaton of 270nm and 300nm. Stokes shift was moved about 20-30nm, under different point excitation. Emission peaks of both Bi3+ and Eu2+ centers appeared at 463nm, 642.5nm by 270nm excitation and 487 nm, 620 nm by 300 nm excitation respectively. After-glow decay cures were also obtained and the shapes of decay curves are similar and it is due to the single hole-trap system by lattice defects.
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