The role of Yb2+ as a scintillation sensitiser in the near-infrared scintillator CsBa2I5:Sm2+

Journal Article (2021)
Author(s)

Casper van Aarle (TU Delft - RST/Luminescence Materials)

Karl W. Krämer (University of Bern)

P. Dorenbos (TU Delft - RST/Luminescence Materials)

Research Group
RST/Luminescence Materials
Copyright
© 2021 C. van Aarle, Karl W. Krämer, P. Dorenbos
DOI related publication
https://doi.org/10.1016/j.jlumin.2021.118257
More Info
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Publication Year
2021
Language
English
Copyright
© 2021 C. van Aarle, Karl W. Krämer, P. Dorenbos
Research Group
RST/Luminescence Materials
Volume number
238
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Abstract

The feasiblity of using Yb2+ as a scintillation sensitiser for CsBa2I5:Sm2+ near-infrared scintillators has been assessed. CsBa2I5 samples with concentrations ranging from 0.3% to 2% Yb2+ and 0–1% Sm2+ have been studied. The scintillation properties have been determined and the dynamics of the scintillation mechanism have been studied through photoluminescence measurements. Radiationless energy transfer between Yb2+ ions plays a key role in increasing the ratio between the spin-forbidden and spin-allowed emission with increasing Yb2+ concentration in samples where Yb2+ is the only dopant. In samples co-doped with Sm2+, the Yb2+ 4f13[F27/2]5d1[LS] and 4f13[F27/2]5d1[HS] states both serve as donor states for radiationless energy transfer to Sm2+ with a rate of energy transfer that is inversely proportional to the luminescence lifetime the respective donor states. At a Sm2+ concentration of 1%, 85% of the Yb2+ excitations are transferred to Sm2+ through radiationless energy transfer. Almost all of the remaining Yb2+ emission is reabsorbed by Sm2+, resulting in nearly complete energy transfer.