energy level modeling of lanthanide defects in sral2o4:eu2+
TRANSCRIPT
Belgian Physical Society, Liège
May 13, 2015
Energy level modeling of lanthanide defects in SrAl2O4:Eu2+
Jonas Joos
Jonas Joos SrAl2O4:Eu2+, electronic structure
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Jonas Joos SrAl2O4:Eu2+, electronic structure
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Technological applications Conversion phosphor
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Jonas Joos SrAl2O4:Eu2+, electronic structure
Jonas Joos Green phosphors for high brightness applications
Lanthanides Electronic transitions
Li6Gd(BO3)3:Tb3+
F. Zhang et al., Physics Procedia 29 (2012), 55-61 3
Jonas Joos SrAl2O4:Eu2+, electronic structure
Lanthanides Electronic transitions
Li6Gd(BO3)3:Tb3+
F. Zhang et al., Physics Procedia 29 (2012), 55-61 3
Jonas Joos SrAl2O4:Eu2+, electronic structure
Lanthanides Electronic transitions
Li6Gd(BO3)3:Tb3+
4fN – 4fN transitions
F. Zhang et al., Physics Procedia 29 (2012), 55-61 3
Jonas Joos SrAl2O4:Eu2+, electronic structure
Lanthanides Electronic transitions
Li6Gd(BO3)3:Tb3+
4fN – 4fN transitions
4fN – 4fN-15d1 transitions
F. Zhang et al., Physics Procedia 29 (2012), 55-61 3
Jonas Joos SrAl2O4:Eu2+, electronic structure
Lanthanides Electronic transitions
Li6Gd(BO3)3:Tb3+
4fN – 4fN transitions
4fN – 4fN-15d1 transitions
Charge transfer transitions
F. Zhang et al., Physics Procedia 29 (2012), 55-61 3
Jonas Joos SrAl2O4:Eu2+, electronic structure
Lanthanides Electronic transitions
Li6Gd(BO3)3:Tb3+
4fN – 4fN transitions
4fN – 4fN-15d1 transitions
Charge transfer transitions
host related
F. Zhang et al., Physics Procedia 29 (2012), 55-61 3
Jonas Joos SrAl2O4:Eu2+, electronic structure
Empirical modeling of lanthanide materials Ground state configuration
NN Ln Lanthanide Q = +II Q = +III
0 La Lanthanum [Xe]5d1
1 Ce Cerium [Xe]4f 2 [Xe]4f 1
2 Pr Praseodymium [Xe]4f 3 [Xe]4f 2
3 Nd Neodymium [Xe]4f 4 [Xe]4f 3
4 Pm Promethium [Xe]4f 5 [Xe]4f 4
5 Sm Samarium [Xe]4f 6 [Xe]4f 5
6 Eu Europium [Xe]4f 7 [Xe]4f 6
7 Gd Gadolinium [Xe]4f 75d1 [Xe]4f 7
8 Tb Terbium [Xe]4f 9 [Xe]4f 8
9 Dy Dysprosium [Xe]4f 10 [Xe]4f 9
10 Ho Holmium [Xe]4f 11 [Xe]4f 10
11 Er Erbium [Xe]4f 12 [Xe]4f 11
12 Tm Thulium [Xe]4f 13 [Xe]4f 12
13 Yb Ytterbium [Xe]4f 14 [Xe]4f 13
14 Lu Lutetium [Xe]4f 14 4
Jonas Joos SrAl2O4:Eu2+, electronic structure
Empirical modeling of lanthanide materials Excited states
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Jonas Joos SrAl2O4:Eu2+, electronic structure
Jonas Joos Green phosphors for high brightness applications
Empirical modeling of lanthanide materials Location of the lowest 5d level
Spectroscopic redshift:
P. Dorenbos, Journal of Solid State Sci. and Technol. 2 (2013), R3001-R3011 5
Jonas Joos SrAl2O4:Eu2+, electronic structure
Empirical modeling of lanthanide materials Energy of charge transfer (CT)
Charge transfer: Ln3+ + XQ- → Ln2+ + X(Q-1)-
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Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+,Dy3+
Persistent luminescence
7 Iedereen wil naar lichtgevende Maria – p. 12
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Photoluminescence
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Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Photoluminescence
emis
sio
n in
ten
sity
(a.
u.)
8
Jonas Joos SrAl2O4:Eu2+, electronic structure
Jonas Joos Green phosphors for high brightness applications
SrAl2O4:Eu2+
Energy level modeling of 4f65d1 configuration
Free Eu2+ ion 4f6 5d1
(free)c
central field RS so cf(ff ) (f ) (f )
RS so cf(fd) (d) (d)
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Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Energy level modeling of 4f65d1 configuration
Free Eu2+ ion 4f6 5d1
c
(free)c
RS so cf(fd) (d) (d)
RScentral f sield o cf(ff ) (f ) (f )
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
cfs
Free Eu2+ ion 4f6 5d1
(free)c
Energy level modeling of 4f65d1 configuration
c
RScentral f sield o cf(ff ) (f ) (f )
RS so cf(fd) (d (d) )
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Free Eu2+ ion 4f6 5d1
(free)c
Energy level modeling of 4f65d1 configuration
c
RScentral f sield cfo(ff ) (f ) (f )
RS so cf(fd) (d (d) )
cfs
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Free Eu2+ ion 4f6 5d1
(free)c
Energy level modeling of 4f65d1 configuration
c
RScentral f sield cfo(ff ) (f ) (f )
RS so cf(fd) (d (d) )
decoupled scheme:
d f(f ) (d) 1 1
f d
f dE E E cfs
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Free Eu2+ ion 4f6 5d1
(free)c
Energy level modeling of 4f65d1 configuration
c
RScentral f sield cfo(ff ) (f ) (f )
RS so cf(fd) (d (d) )
decoupled scheme:
d f(f ) (d) 1 1
f d
f dE E E
4f6 core: similar to Eu3+:
7 F
6J
0J
cfs
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
cfs
Free Eu2+ ion 4f6 5d1
(free)c
cfs (free)
Energy level modeling of 4f65d1 configuration
c
RScentral f sield cfo(ff ) (f ) (f )
RS so cf(fd) (d (d) )
decoupled scheme:
d f(f ) (d) 1 1
f d
f dE E E
4f6 core: similar to Eu3+:
7 F
6J
0J 9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Energy (eV)
Free Eu2+ ion 4f6 5d1
(free)c5.0
4.0
3.0
cfs (free)
Energy level modeling of 4f65d1 configuration
c blue
cfs blue
central field RS so cf(ff ) f (f )( )
RS so cf(fd) (d (d) )
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Energy (eV)
Free Eu2+ ion 4f6 5d1
(blue)D
(free)c5.0
4.0
3.0
cfs (free)
Energy level modeling of 4f65d1 configuration
central field RS so cf(ff ) f (f )( )
RS so cf(fd) (d (d) )
cfs blue
c blue
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Energy (eV) Energy (eV)
cfs (green)
Free Eu2+ ion 4f6 5d1
c (green)
(green)D
(free)c
4.0
3.0
5.0 5.0
4.0
3.0
cfs (free)
cfs (free)
Energy level modeling of 4f65d1 configuration
cfs blue
(blue)D
c blue
9
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Connection with crystallography
Monoclinic unit cell (P21) Two nonequivalent Sr-sites (C1)
Sr1 Sr2
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Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Connection with crystallography
Monoclinic unit cell (P21) Two nonequivalent Sr-sites (C1) Empirical relations: Prediction: Measurement
10
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:Eu2+
Connection with crystallography
Monoclinic unit cell (P21) Two nonequivalent Sr-sites (C1) Empirical relations: EuSr1: green emission EuSr2: blue emission
10
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme - Input
VB
CB
Eu2+ lowest 4f
Eu3+ lowest 4f
Coulomb correlation energy for Eu2+/Eu3 obtained from Ce3+ spectrum:
P. Dorenbos, J. Lumin 135, 93 (2013) D. Jia, J. Lumin. 117, 170 (2006)
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Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme - Input
VB
CB
Coulomb correlation energy for Eu2+/Eu3 obtained from Ce3+ spectrum:
P. Dorenbos, J. Lumin 135, 93 (2013) D. Jia, J. Lumin. 117, 170 (2006)
11
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme - Input
VB
CB
Coulomb correlation energy for Eu2+/Eu3 obtained from Ce3+ spectrum Chemical shift 4f level Eu2+ obtained:
P. Dorenbos, J. Lumin 135, 93 (2013) D. Jia, J. Lumin. 117, 170 (2006)
11
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme - Input
VB
CB
Coulomb correlation energy for Eu2+/Eu3 obtained from Ce3+ spectrum Chemical shift 4f level Eu2+ obtained: Host referred binding energy from Eu3+ CT:
11
VB
vacuum
EuSr1 EuSr2
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme - Input
VB
CB
Coulomb correlation energy for Eu2+/Eu3 obtained from Ce3+ spectrum Chemical shift 4f level Eu2+ obtained: Host referred binding energy from Eu3+ CT:
11
VB
vacuum
EuSr1 EuSr2
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme
Trivalent lanthanides
Sr1 Sr2
13
Jonas Joos SrAl2O4:Eu2+, electronic structure
SrAl2O4:LnQ+
Lanthanide VRBE scheme
Divalent lanthanides
Sr1 Sr2
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Jonas Joos SrAl2O4:Eu2+, electronic structure
Belgian Physical Society, Liège
May 13, 2015
Energy level modeling of lanthanide defects in SrAl2O4:Eu2+
Jonas Joos
Jonas Joos SrAl2O4:Eu2+, electronic structure