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Lanthanum-stabilized europium-doped cubic barium chloride: An efficient x-ray phosphor
We report the photoluminescence and x-ray luminescence of lanthanum-stabilized cubic barium chloride with europium ( Eu 2 + ) doping, of general composition Ba 1 − x − y Eu y La x Cl 2 + x . X-ray diffraction patterns confirm that the material adopts a cubic fluorite structure for x = 0.125 and 0 &l...
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Published in: | Journal of applied physics 2010-04, Vol.107 (8), p.083516-083516-7 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | We report the photoluminescence and x-ray luminescence of lanthanum-stabilized cubic barium chloride with europium
(
Eu
2
+
)
doping, of general composition
Ba
1
−
x
−
y
Eu
y
La
x
Cl
2
+
x
. X-ray diffraction patterns confirm that the material adopts a cubic fluorite structure for
x
=
0.125
and
0
<
y
<
0.1
. The photoluminescence shows an intense band comprising two components with maxima at 420 and 394 nm. The 394 nm band is assigned to
Eu
2
+
substituting for
Ba
2
+
giving a site of cubic symmetry, based on the excitation spectra which show a
T
2
g
band and
E
g
band similar to those in cubic
SrCl
2
:
Eu
. The 420 nm band has a very different lifetime and excitation spectrum and is assigned to
Eu
2
+
ions which have an associated chlorine interstitial ion. The two bands are also found in the x-ray luminescence spectra. For both bands, and an additional minor emission at 520 nm found only at low temperatures and for high Eu concentrations, there is a common excitation in the UV from 150 to 200 nm which we attribute to excitons associated with the high concentration of chlorine interstitials. ESR measurements support a two-site model for the interpretation of the optical spectra. A measurement of the x-ray luminescence intensity compared to a standard commercial
Gd
2
O
2
S
:
Tb
phosphor sheet shows approximately equal brightness. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.3369162 |