LumiLab Department of Solid State Sciences

Ghent UniversityBelgium

iCom, Budva, MontenegroSeptember 4, 2015

Jonas J. Joos, Dirk Poelman, Philippe F. Smet

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Nonequivalent lanthanide defects: energy level modeling

Energy levels, a tool for spectroscopy

1

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

4f2 4f5d CT host*

many-body diagram

Pr3+

Energy levels, a tool for spectroscopy

1

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

4f2 4f5d CT host*

many-body diagram

Pr3+

Energy levels, a tool for spectroscopy

1

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

4f2 4f5d CT host*

many-body diagramone-electron diagram

Pr3+

Energy levels, a tool for spectroscopy

1

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

4f2 4f5d CT host*

many-body diagramone-electron diagramcharge-state transition level

Pr3+

Empirical energy level schemes

2

CaGa2S4

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Empirical energy level schemes

2

CaGa2S4

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Empirical energy level schemes

2

CaGa2S4

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

easy!

Multiple defects

3

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Easy: All lanthanide ions do the same

example: CaGa2S4

Harder: All lanthanides do the same

example: SrAl2O4

Hard: Some lanthanides act “special”

example: SrGa2S4

Sr1 Sr2

Eu2+ Ce3+

Multiple defects

3

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Easy: All lanthanide ions do the same

example: CaGa2S4

Harder: All lanthanides do the same

example: SrAl2O4

Hard: Some lanthanides act “special”

example: SrGa2S4

Sr1 Sr2

Eu2+ Ce3+

Site-selective PL spectroscopy

4

Eu2+

J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

Sr1 Sr2

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Site-selective PL spectroscopy

4

Eu2+

Ce3+

D. D. Jia, J. Lumin. 117, 170 (2006)

Sr1 Sr2

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Site-selective PL spectroscopy

4 J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

VB

Eu2+

Ce3+

Eu3+

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Site-selective PL spectroscopy

4 J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

VB

vacuum

EuSr1 EuSr2

Eu2+

Ce3+

Eu3+

Sr1 Sr2

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Two-site energy level scheme

5

Trivalent lanthanides

Sr1Sr2

J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Two-site energy level scheme

6

Divalent lanthanides

Sr1Sr2Sr1

Sr2

J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Two-site energy level scheme

7

Divalent lanthanides

J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Sr1Sr2

Two-site energy level scheme

7

Divalent lanthanides

J. Botterman, J. J. Joos, P. F. Smet, Phys. Rev. B 90, 085147 (2014)

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Multiple defects

3

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Easy: All lanthanide ions do the same

example: CaGa2S4

Harder: All lanthanides do the same

example: SrAl2O4

Hard: Some lanthanides act “special”

example: SrGa2S4

Sr1 Sr2

Eu2+ Ce3+

Multiple defects

3

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Easy: All lanthanide ions do the same

example: CaGa2S4

Harder: All lanthanides do the same

example: SrAl2O4

Hard: Some lanthanides act “special”

example: SrGa2S4

Sr1 Sr2

Eu2+ Ce3+

PL spectroscopy Eu2+ and Ce3+

8

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

energy (eV)

PL spectroscopy Eu2+ and Ce3+

8

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

energy (eV)

PL spectroscopy Eu2+ and Ce3+

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

8 energy (eV)

PL spectroscopy Eu2+ and Ce3+

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

8 energy (eV)

PL spectroscopy Eu2+ and Ce3+

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

8 energy (eV)

PL spectroscopy Eu2+ and Ce3+

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

8 energy (eV)

PL spectroscopy Eu2+ and Ce3+

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

8 energy (eV)

Local environment from EPR

9

SrGa2S4:Eu2+ SrGa2S4:Ce3+

W. L. Warren et al., Appl. Phys. Lett. 70, 478 (1997)

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

SrGa2S4:Ce3+

Repercussions on E-level scheme

10

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Repercussions on E-level scheme

10

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Multiple defects

3

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Easy: All lanthanide ions do the same

example: CaGa2S4

Harder: All lanthanides do the same

example: SrAl2O4

Hard: Some lanthanides act “special”

example: SrGa2S4

Sr1 Sr2

Eu2+ Ce3+

Conclusions

11

Realistic materials often require more complex models

Very distinct experimental features burried in uncertainty intervals

General physical insight most important merit

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

LumiLab Department of Solid State Sciences

Ghent UniversityBelgium

iCom, Budva, MontenegroSeptember 4, 2015

Jonas J. Joos, Dirk Poelman, Philippe F. Smet

Jonas Joos Nonequivalent lanthanide defects: energy level modeling

Nonequivalent lanthanide defects: energy level modeling