Modeling and Assessment of Afterglow Decay Curves from Thermally Stimulated Luminescence of Complex Garnets

Vasilii M Khanin; Ivan I Vrubel; Roman G Polozkov; Ivan A Shelykh; Ivan D Venevtsev; Andries Meijerink; Herfried Wieczorek; Jack Boerekamp; Sandra Spoor; Piotr A Rodnyi; Cees Ronda

doi:10.1021/acs.jpca.8b11778

Modeling and Assessment of Afterglow Decay Curves from Thermally Stimulated Luminescence of Complex Garnets

J Phys Chem A. 2019 Mar 7;123(9):1894-1903. doi: 10.1021/acs.jpca.8b11778. Epub 2019 Feb 25.

Authors

Affiliations

¹ Philips Healthcare , High Tech Campus 4 , 5656 AE Eindhoven , The Netherlands.
² Utrecht University , Princetonplein 5 , 3584 CC Utrecht , The Netherlands.
³ ITMO University , Kronverksky 49 , 197101 St. Petersburg , Russia.
⁴ Science Institute , University of Iceland , Dunhagi 3 , IS-107 , Reykjavik , Iceland.
⁵ Peter the Great St. Petersburg Polytechnic University , Polytekhnicheskaya 29 , 195251 St. Petersburg , Russia.

PMID: 30775917
DOI: 10.1021/acs.jpca.8b11778

Abstract

Afterglow is an important phenomenon in luminescent materials and can be desired (e.g., persistent phosphors) or undesired (e.g., scintillators). Understanding and predicting afterglow is often based on analysis of thermally stimulated luminescence (TSL) glow curves, assuming the presence of one or more discrete trap states. Here we present a new approach for the description of the time-dependent afterglow from TSL glow curves using a model with a distribution of trap depths. The method is based on the deconvolution of the energy dependent density of occupied traps derived from TSL glow curves using Tikhonov regularization. To test the validity of this new approach, the procedure is applied to experimental TSL and afterglow data for Lu₁Gd₂Ga₃Al₂O₁₂:Ce ceramics codoped with 40 ppm of Yb³⁺ or Eu³⁺ traps. The experimentally measured afterglow curves are compared with simulations based on models with and without the continuous trap depth distribution. The analysis clearly demonstrates the presence of a distribution of trap depths and shows that the new approach gives a more accurate description of the experimentally observed afterglow. The new method will be especially useful in understanding and reducing undesired afterglow in scintillators.