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Defects in phosphors affect not only luminescence intensity but also emission peak width, decay time, and afterglow. The green phosphor β-SiAlON:Eu2+ exhibits the green emission of Eu2+ at 520 nm and the blue emission of nitrogen vacancies at 460 nm in time-resolved fluorescence measurements. The decay time of the intrinsic Eu2+ transition is 0.7 us, but afterglow is detected from 50 us to 0.01 s. This afterglow decay curve is the same for the green emission of Eu2+ and the blue emission of nitrogen vacancies, suggesting that the defect levels of the nitrogen vacancies affect the Eu2+ transition. The afterglow decay curves were analyzed using the formula of the general-order kinetics, (1 + 𝑡/𝜏B)−𝑛, where 𝑛 is the decay power and 𝜏B is the decay time. This equation is generally used when analyzing afterglow on the order of seconds to hours but has not been examined systematically applied in samples with different temperatures and concentrations on the order of nanoseconds to milliseconds.The decay power 𝑛 is approximately 1 for all Eu2+ concentrations (x = 0.001 to 0.3) and undoped β-SiAlON. The decay time 𝜏B is correlated with the density of the nitrogen vacancies determined by electron spin resonance. Furthermore, the value of 𝑛 is approximately 1 for 50 us to 0.01 s and 0.3 for 1–1000 s. Thus, the luminescence mechanism of Eu2+ can be discussed by comparing 𝑛 and 𝜏B obtained form the decay curves. In addition, several different Eu2+ -doped phosphors, namely SrAl2O4:Eu2+, Dy3+, CaAlSiN3:Eu2+, and CaS:Eu2+, Tm3+, are studied.

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• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

  This is the Accepted Manuscript version of an article accepted for publication in Journal of Physics D: Applied Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://dx.doi.org/10.1088/1361-6463/ad2294

Keyword: luminescence, decay curve, afterglow, phosphor, SiAlON, europium

Date published: 2024-05-03

Publisher: IOP Publishing

Journal:

• Journal of Physics D: Applied Physics (ISSN: 13616463) vol. 57 issue. 18 185101

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Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4893

First published URL: https://doi.org/10.1088/1361-6463/ad2294

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Updated at: 2025-02-07 12:30:36 +0900

Published on MDR: 2025-02-07 12:30:36 +0900