Experimental and numerical analysis of Tm&lt;sup&gt;2&lt;/sup&gt;&lt;sup&gt;+&lt;/sup&gt; excited-states dynamics and luminescence in CaX&lt;sub&gt;2&lt;/sub&gt; (X = Cl, Br, I)

Plokker, M.P.; van der Knijff, I.C.; de Wit, A.V.; Voet, B.; Woudstra, T.; Khanin, V.; Dorenbos, P.; van der Kolk, E.

doi:10.1088/1361-648X/abfa5d

Experimental and numerical analysis of Tm²⁺ excited-states dynamics and luminescence in CaX₂ (X = Cl, Br, I)

Title

Experimental and numerical analysis of Tm²⁺ excited-states dynamics and luminescence in CaX₂ (X = Cl, Br, I)

Author

Plokker, M.P. (TU Delft RST/Luminescence Materials)
van der Knijff, I.C. (TU Delft Optical Technologies)
de Wit, A.V. (Student TU Delft)
Voet, B. (Student TU Delft)
Woudstra, T. (Student TU Delft)
Khanin, V. (TU Delft RST/Luminescence Materials)
Dorenbos, P. (TU Delft RST/Luminescence Materials)
van der Kolk, E. (TU Delft RST/Luminescence Materials)

Date

2021

Abstract

The prospect of using Tm²⁺-doped halides for luminescence solar concentrators (LSCs) requires a thorough understanding of the temperature dependent Tm²⁺ excited states dynamics that determines the internal quantum efficiency (QE) and thereby the efficiency of the LSC. In this study we investigated the dynamics in CaX₂:Tm²⁺ (X = Cl, Br, I) by temperature- and time-resolved measurements. At 20 K up to four distinct Tm²⁺ emissions can be observed. Most of these emissions undergo quenching via multi-phonon relaxation below 100 K. At higher temperatures, only the lowest energy 5d–4f emission and the 4f–4f emission remain. Fitting a numerical rate equation model to the data shows that the subsequent quenching of the 5d–4f emission is likely to occur initially via multi-phonon relaxation, whereas at higher temperatures additional quenching via interband crossing becomes thermally activated. At room temperature only the 4f–4f emission remains and the related QE becomes close to 30%. Possible reasons for the quantum efficiency not reaching 100% are provided.

Subject

CaCl:Tm CaBr:Tm CaI:Tm+
Luminescence quenching
Photoluminescence
Rate equations modelling
Tm doped halides
Tm excited states dynamics

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http://resolver.tudelft.nl/uuid:2235501a-5ecc-4c13-a8f6-e98dfe28546d

DOI

https://doi.org/10.1088/1361-648X/abfa5d

ISSN

0953-8984

Source

Journal of Physics: Condensed Matter, 33 (25)

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