On the Correlation between the Composition of

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


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+


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+


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)


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+


(420)

3.5

3+

3+

Photon energy (eV)


3+

Lu3Al3MgSiO12:0.1% 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