Plokker, M.P.; Hoogsteen, W.; Abellon, R.D.; Krämer, K. W.; van der Kolk, E. (2020). Concentration and temperature dependent luminescence properties of the SrI2-TmI2 system. Journal of luminescence, 225, p. 117327. Elsevier 10.1016/j.jlumin.2020.117327
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The concentration dependent luminescence of the SrI2-TmI2 system was investigated. For Tm2+ concentrations up to 5 mol %, the quantum efficiency (QE) of the 2F5/2→2F7/2 emission exhibits a constant value above 50%. The QE drops for higher Tm2+ concentrations, partly due to concentration quenching, as evidenced by a decreasing luminescence lifetime of the 2F5/2→2F7/2 emission, and partly due to the formation of a second crystal phase with CdCl2 structure, in which the 2F5/2→2F7/2 emission is quenched. The temperature and time dependent relaxation dynamics were studied to identify the origin of the limited QE for Tm2+-doping levels below 5 mol %. An anti-correlation between the 5d-4f (3H6,t2g)S=3/2→2F7/2 and 4f-4f 2F5/2→2F7/2 emission intensities was found and rationalised by non-radiative,
thermally stimulated, inter-configurational 5d-4f relaxation to the emitting 2F5/2 level of Tm2+. Both, the rise time of the 4f-4f and the decay time of the 5d-4f emission become shorter with increasing temperature. We suggest a similar non-radiative relaxation from the 5d level towards the 2F7/2 ground state to limit the QE below unity. This route becomes more efficient when the 5d (3H6,t2g)S=3/2 state moves closer to the 4f 2F5/2 and 2F7/2 states, which is the case for the CdCl2 phase with a QE close to zero.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP) |
UniBE Contributor: |
Krämer, Karl |
Subjects: |
500 Science > 530 Physics 500 Science > 540 Chemistry |
ISSN: |
0022-2313 |
Publisher: |
Elsevier |
Language: |
English |
Submitter: |
Karl Krämer |
Date Deposited: |
24 Jun 2020 17:23 |
Last Modified: |
05 Dec 2022 15:39 |
Publisher DOI: |
10.1016/j.jlumin.2020.117327 |
BORIS DOI: |
10.7892/boris.144773 |
URI: |
https://boris.unibe.ch/id/eprint/144773 |
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