phosphors were prepared under a reducing atmosphere by solid-state reaction using CaCl
2
as flux medium and starting materials. Samples sintered under different CaCO
3
concentration
different temperatures and different time were obtained. The effect of these conditions on the structure was studied by X-ray diffraction (XRD). The synthetic conditions were optimized at the molar ratio of starting materials CaCO
3
: Mg(OH)
2
: SiO
2
: CaCl
2
equal to 1.5 : 1 : 2 : 2.4
sintering temperature 900 ℃ and sintering time 3 h. The photoluminescence (PL) spectra of the as-prepared phosphor powders were measured. The results indicated that the Ca
2
MgSi
2
O
7
: Eu
2+
phosphor can be effectively excited by the light in the wavelength range of 360~480 nm and emission spectrum shows a broad green emission band centered at 529 nm with a bright green emission. And it is possible to determine the distribution of this broad emission band in the spectrum associated with transition from the 4f5d level of Eu
2+
ion which only replaces the Ca
2+
ion site with a coordinate number of eight. Furthermore
the broad green emission band is asymmetric as a result of the re-absorption of the blue light by the green-emission light. The Ca
2
MgSi
2
O
7
∶ Eu
2+
phosphors were also synthesized at 1 200 ℃ for 4 h in a reducing atmosphere using H
3
BO
3
as flux medium and CaCO
3
Mg(OH)
2
SiO
2
as starting materials. Comparing the high temperature and low temperature methods
we found that their exitaton spectrum profiles are different
and the emission intensity of Ca
2
MgSi
2
O
7
∶
x
Eu
2+
(
x
=0.01
0.02
0.03
0.04
0.07) phosphor prepared at 900 ℃ is higher than that of powders prepared at 1 200 ℃.
关键词
Keywords
references
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