Fig.1. XRD patterns of Lu3(Al,Ga)5O12 (a) and (Y,Lu)3Al3MgSiO12 (b) doped ... 1. Wavelength (nm). 200 250 300 350 400 450 500 550 600 650 700 750 800.
On the Correlation between the Composition of Garnet Type Materials and their Photoluminescence Properties A. Katelnikovasa,b, D. Uhlicha, H. Bettentrupa, J. Plewaa, A. Kareivab and T. Jüstela aDepartment
of Chemical Engineering, Münster University of Applied Sciences, Stegerwaldstr. 39, D-48565 Steinfurt, Germany bDepartment of General and Inorganic Chemistry Chemistry, Vilnius University University, Naugarduko 24, LT-03225 Vilnius, Lithuania
6th Laser Ceramics Symposium, 2010 December 5-8, Münster, Germany
3
2.5
6
2
5
4
90
7
3+
50
Lu3Al4GaO12:0.1% Nd
40
Lu3Al3Ga2O12:0.1% Nd
3+ 3+
30
Lu3Al2Ga3O12:0.1% Nd
20
L 3AlGa Lu AlG 4O12:0.1% 0 1% Nd
10
Lu3Ga5O12:0.1% Nd
3+
3+
7
6
50
55
(420)
60
15
20
25
30
35
40
(631) (444) (543) (640) (721) (642)
(400)
(321)
(220)
(211)
(631) (444) (543) (640) (721) (642)
(532) (620) (541)
(400)
(332) (422) (431)
(521) (440)
45
45
50
55
60
2
4 3+
3+
Lu3Al4GaO12:0.1% Nd (em=401nm)
6
3+
Lu3Al3Ga2O12:0.1% Nd (em=400nm) 5
3+
Lu3Al2Ga3O12:0.1% Nd
3+
Lu3AlGa4O12:0.1% Nd 3+
Lu3Ga5O12:0.1% Nd 1.5
1.0
3+
Lu3Al2Ga3O12:0.1% Nd (em=400nm) 3+
Lu3AlGa4O12:0.1% Nd (em=400nm)
4
3+
Lu3Ga5O12:0.1% Nd (em=399nm) 3 2
05 0.5
1
400
450
500
550
600
650
700
750
800
0 150
Wavelength (nm)
200
250
Fig. 2. Reflection spectra of Lu3(Al,Ga)5O12:0.1%Nd3+
Photon energy (eV)
Photon energy (eV) 4.5 4
3.5
3
2.5
2
4.0
100
6
5
4
3
8 3+
Lu3Al5O12:1% Pr
Lu3Al4GaO12:1% Pr
30
Lu3Al3Ga2O12:1% Pr
20
Lu3Al2Ga3O12:1% Pr
3+ 3+ 3+ 3+
3+
Lu3Al3Ga2O12:1% Pr (em=357nm) Lu3Al2Ga3O12:1% Pr (em=350nm) 3+
Lu3AlGa4O12:1% Pr (em=486nm) 3+
Lu3Ga5O12:1% Pr (em=485nm) 485nm)
1.5
1.0 1.0
3
2
ex = 160 nm 3+
Y2LuMg2AlSi2O12:1% Pr
5
YLu2Mg2AlSi2O12:1% Pr
3+
Lu3Mg2AlSi2O12:1% Pr
4 3 2 1
0.5
0.5
Lu3AlGa4O12:1% Pr
10
Lu3Ga5O12:1% Pr
1.5
4
3+
3+
3+
5
3+
6
3+
2.0
6
Y3Mg2AlSi2O12:1% Pr
Lu3Al5O12:1% Pr (em=367nm)
3+
3+
Lu3AlGa4O12:1% Pr
2.0
7
Lu3Al4GaO12:1% Pr (em=361nm)
Lu3Al2Ga3O12:1% Pr
2.5
4 3+
2.5
Lu3Al3Ga2O12:1% Pr
3.0
Photon energy (eV)
5
Lu3Al4GaO12:1% Pr
6
50 40
Fig. 5. Simplified Dieke Diagram of Pr3+ involving the lowest crystal-field component of the [Xe]4f15d1 config.,
3+
Intensity (a.u.)
Intensity x x10 (counts)
60
6
3+ 3+
70
7
3.0
Lu3Al5O12:1% Pr
3.5
80
350
Photon energy (eV) 2
ex = 160 nm
90
300
Wavelength (nm)
Fig. 4. Excitation spectra of Lu3(Al,Ga)5O12:0.1%Nd3+
Fig. 3. Emission spectra of Lu3(Al,Ga)5O12:0.1%Nd3+
5
350
Intensity x x10 (counts)
300
0.0 200 250 300 350 400 450 500 550 600 650 700 750 800
Wavelength (nm)
3+
Lu3Ga5O12:1% Pr
0 250
300
350
400
450
500
550
600
650
700
750
0.0 200 250 300 350 400 450 500 550 600 650 700 750 800
800
0
0.0 150
Wavelength (nm)
200
250
Fig. 7. Emission spectra of Lu3(Al,Ga)5O12:1%Pr3+
Fig. 6. Reflection spectra of Lu3(Al,Ga)5O12:1%Pr3+ Photon energy (eV) 4.5 4
3.5
3
2.5
2.6
2.4
2.2
2
1.6
8
Lu3Mg2AlSi2O12:0.25% Ce
7
Normalized intensity
Y3Mg2AlSi2O12:2% Ce
30
Y2LuMg2AlSi2O12:2% Ce
20
YLu2Mg2AlSi2O12:2% Ce
10
Lu3Mg2AlSi2O12:2% Ce
3+ 3+
Photon energy (eV) 2.6 2.5 2.4 2.3 2.2
2.5
2.1
2
1.9
Y2LuAl3MgSiO12:0.25% Ce
6
1.6 3+
YLu2Al3MgSiO12:0.25% Ce YAG:Ce
3+
3+
Y3Al3MgSiO12:0.25% Ce
3+
1.7
3+
3+
Y3Mg2AlSi2O12:0.25% Ce
1.8
Lu3Al3MgSiO12:0.25% Ce 3+
Intensity (a.u.)
3+
40
3
Lu3Al3MgSiO12:0.25% Ce
YLu2Al3MgSiO12:0.25% Ce
Y2LuMg2AlSi2O12:0.25% Ce
50
3.5
3+
YLu2Mg2AlSi2O12:0.25% Ce
60
4
3+
3+
70
4.5 YAG:Ce
YAG:Ce
80
Wavelength (nm)
Fig. 9. Emission spectra of (Y,Lu)3Mg2AlSi2O12:1%Pr3+
Photon energy (eV)
1.8
90
200 250 300 350 400 450 500 550 600 650 700 750 800
350
Fig. 8. Excitation spectra of Lu3(Al,Ga)5O12:1%Pr3+
Photon energy (eV) 2
100
300
Wavelength (nm)
Wavelength (nm)
3+
Y2LuAl3MgSiO12:0.25% Ce
Normalized intensity
Reflection (%)
40
3+
0 250
Reflection (%)
35
5
3+
2.0
30
Lu3Al5O12:0.1% Nd (em=401nm)
Lu3Al3Ga2O12:0.1% Nd
6
Lu3Al5O12:0.1% Nd
8
3+
Lu3Al5O12:0.1% Nd
2.5
(321)
(220)
(211)
2
ex = 160 nm
Intensity (a.u.)
Intensity x10 (counts)
70
25
33-0040 > Y3Al5O12
2
Lu3Al4GaO12:0.1% Nd
60
20
33-0040 > Y3Al5O12
Fig.1. XRD patterns of Lu3(Al,Ga)5O12 (a) and (Y,Lu)3Al3MgSiO12 (b) doped with 0.1% Nd3+ sintered at 1600 °C.
3+
80
Reflection (%)
15
3+
Y3Al3MgSiO12:0.1% Nd
(532) (620) (541)
3+
Lu3Al5O12:0.1% Nd
3+
Y2LuAl3MgSiO12:0.1% Nd
Photon energy (eV)
3
100 3.0
YLu2Al3MgSiO12:0.1% Nd
Relative inten nsity
Relative inten nsity
3+
Lu3Al3Ga2O12:0.1% Nd
(420)
3.5
3+
3+
Photon energy (eV)
Photon energy (eV) 4
3+
Lu3Al3MgSiO12:0.1% Nd
Lu3Al2Ga3O12:0.1% Nd
In the present study, the luminescent properties of Nd3+, Pr3+ and Ce3+ doped garnet type host lattices, namely Lu3(Al1-yyGay)5O12, (Y1-xLux)3Mg2AlSi2O12 and (Y1-xLux)3Al3MgSiO12, are discussed as a function of their composition. 4.5
b
(521) (440)
Garnet is the common name of a group of cubic minerals belonging to the nesosilicates, which contain solely isolated tetrahedral [SiO4]4- units. The general formula of garnets is C3A2D3O12, which, in case of natural garnets, can be written as C3A2(SiO4)3, where h C = Fe F 2+, Mg M 2+, Ca C 2+ and d A = Al3+, Fe F 3+, Cr C 3+ 3+ and V . In the general formula, O denotes oxygen and C, A, D symbolize cations occupying the dodecahedral, octahedral and tetrahedral sites, respectively. Artificial garnets according to the formula (Y1-xLux)3(Al1-yGay)5O12 are applied as hosts for laser gain media, scintillators, and LED phosphors.
3+
Lu3Ga5O12:0.1% Nd
(332) (422) (431)
a
Introduction
5 4 3
3+
Y3Al3MgSiO12:0.25% Ce
2
3+
1
YAG:Ce
0 250
300
350
400
450
500
550
600
650
ex = 450 nm 700
Wavelength (nm)
Fig. 10. Reflection spectra of (Y Lu)3Mg2AlSi2O12:2%Ce3+ (Y,Lu)
750
800
500
550
600
650
700
750
800
Wavelength (nm)
Fig. 11. Emission spectra of (Y,Lu) (Y Lu)3Mg2AlSi2O12:0.25%Ce :0 25%Ce3+
850
0 250
300
350
400
450
500
Wavelength (nm)
Fig. 12. Excitation spectra of (Y,Lu) (Y L )3Al3MgSiO M SiO12:0.25%Ce 0 25%C 3+
550
500
550
600
650
700
750
800
Wavelength (nm)
Fig. 12. Emission spectra of (Y,Lu) (Y Lu)3Al3MgSiO12:0.25%Ce :0 25%Ce3+
Conclusions In this work, we demonstrated that a modification of the LuAG host by Ga, Y, or Si and Mg results in strong changes with respect to the optical spectra of of Ce3+, Pr3+, or Nd3+ located onto the dodecahedral garnet sites. Ce3+ emits in LuAG:Ce at around 525 nm. Any replacement of Lu by Y or Al by Mg and Si, results in a red-shift. Even a 600 nm emitting garnet is feasible by using Y3AlMg2Si2O12 as a host. Pr3+ doped garnets show very peculiar spectra, due to presence of 4f-5d (UV range) and 4f-4f (visible range) transitions. The ratio of band to line emission can be easily tuned by the garnet composition. While LuAG:Pr mainly shows several 4f-5d emission bands in the UV range, all Si/Mg comprising garnets the 4f-4f line transitions dominate the spectrum. The well known LuAG:Nd reveals intense visible emission lines upon 160 nm excitation. The replacement of Al3+ by Ga3+ results in a band gap shift from 180 to 215 nm. At the same time, the luminescence of Nd3+ in the visible range is completely quenched, which reveals that the ET from the host lattice excitons to the 4f-4f states of the dopant Nd3+ is mediated by the high lying 4f5d-levels at 195 and 220 nm