Extending the afterglow in CaAl_2O_4:Eu,Nd persistent phosphors by electron beam annealing

Smet, Philippe; Avci, Nursen; Eeckhout, Koen Van den; Poelman, Dirk

doi:10.1364/ome.2.001306

Cited by 37 publications

(22 citation statements)

References 29 publications

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“…During the first few minutes, the emission intensity drops rapidly, but this decrease slows down over time. As reported previously, 64 the photopic intensity (not shown) drops below the 0.32 mcd/m 2 threshold after 11 h, but the afterglow remains visible with the unaided dark-adapted eye for at least 72 h.…”

Section: Emission and Afterglowsupporting

confidence: 87%

“…64. The pellets produced using this procedure have an afterglow intensity of about three times that of commercially available powder, and the afterglow duration extends to 10 h.…”

Section: A Experimentalmentioning

confidence: 97%

“…Possibly, this is due to the alternative preparation technique of the sample, and it could be an explanation for the improved afterglow lifetime of the sample compared to a benchmark CaAl 2 O 4 :Eu,Nd persistent phosphor, as reported previously. 64 Aitasalo et al 41 found that the glow curve for CaAl 2 O 4 :Eu,Nd consists of two overlapping peaks. The main TL peak, around 350 K, was present in all CaAl 2 O 4 :Eu,R (R = rare earth) samples and is therefore assumed to be related to the lattice rather than to the codopants.…”

Section: Thermoluminescence Experimentsmentioning

confidence: 99%

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Revealing trap depth distributions in persistent phosphors

et al. 2013

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Persistent luminescence or afterglow is caused by a gradual release of charge carriers from trapping centers. The energy needed to release these charge carriers is determined by the trap depths. Knowledge of these trap depths is therefore crucial in the understanding of the persistent luminescence mechanism. Unfortunately, the trap depths in persistent phosphors are often difficult to evaluate in an accurate and reliable way. The existing analysis methods are mostly based on single experiments, or they ignore the possibility of a continuous distribution of trap depths. We present a procedure to accurately probe the activation energies, even in the presence of a continuous distribution of energy levels. By performing a series of thermoluminescence experiments with varying excitation duration and at varying excitation temperature, and employing the initial rise analysis method, the depth and shape of such a distribution can be estimated. As an example, we investigated the trap system in the violet persistent phosphor CaAl 2 O 4 :Eu,Nd, and show that it consists of a Gaussian-shaped distribution of trap depths. The maximal density of traps lies in the region around 0.9 eV, but the distribution extends to 0.7 eV on the shallow side and 1.2 eV on the deep side. The described procedure can be used to obtain a clear view of the trap system in other persistent phosphors as well. This can lead to a better understanding of the nature of these trapping centers, and the role they play in the persistent luminescent mechanism.

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Section: Emission and Afterglowsupporting

confidence: 87%

“…64. The pellets produced using this procedure have an afterglow intensity of about three times that of commercially available powder, and the afterglow duration extends to 10 h.…”

Section: A Experimentalmentioning

confidence: 97%

Section: Thermoluminescence Experimentsmentioning

confidence: 99%

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Revealing trap depth distributions in persistent phosphors

et al. 2013

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“…Not long after this discovery an improvement was madeby SrAl2O4:Eu co-doping with dysprosium, the already intensive and lengthy afterglow was enhanced even more and now could reach more than 10 h [6]. With this, the study of Eu activated alkaline earth materials and other compounds beganadding different aluminates, silicates and phos-phates to the list of persistent phosphors [7][8][9][10][11]. They all share the same blue-green emission colour, as they all contain Eu 2+ as the luminescence centre.…”

Section: Sral 2 O 4 As a Host Materialsmentioning

confidence: 99%

Recent progress in understanding the persistent luminescence in SrAl₂O₄:Eu,Dy

Vitola

Millers

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et al. 2019

Materials Science and Technology

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Ever since the discovery of SrAl2O4:Eu,Dy persistent afterglow material, that can intensively glow up to 20 h, the mechanism of long-lasting luminescence has been a popular area of research. The research is focused on discovering the mechanism of persistent luminescence in order to prolong the duration and intensity of afterglow in a controlled way. Although most researchers agree on the general things, there are still many unclarities and ambiguities to discuss upon. This review paper briefly sketches in the highlights of past research on the luminescence mechanism in SrAl2O4:Eu,Dy, mainly focusing on the research conducted in the past decade dedicated to clearing these ambiguities. This paper provides an overview of the latest persistent luminescence mechanisms offered by researchers.

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“…The first group is based on the use of divalent europium as luminescence center, often with other rare earth ions as co-dopants. The most studied materials in this group are CaAl 2 O 4 :Eu,Nd [8,9], Sr 2 MgSi 2 O 7 :Eu,Dy [10], SrAl 2 O 4 :Eu,Dy [5,11] and Sr 4 Al 14 O 25 :Eu,Dy [12]. An extensive overview is given in the review by Van den Eeckhout et al [7].…”

Section: Introductionmentioning

confidence: 99%

Persistent luminescence in nitride and oxynitride phosphors: A review

et al. 2014

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The research field of persistent luminescence has experienced a strong growth in the past two decades, with a steady development of new materials and applications. Here we give an overview of the recent progress in a specific class of host materials, namely oxynitride and nitride persistent phosphors. These are interesting hosts to explore because of their unique characteristics, such as chemical stability and tunability of the emission over the entire visible range upon doping with divalent europium. To yield persistent luminescence however, codopants have to be added or the synthesis conditions have to be adjusted. Specific materials, such as Ca 2 Si 5 N 8 :Eu,Tm and BaSi 2 O 2 N 2 :Eu, are highlighted and their properties are put into the context of emerging applications such as in vivo imaging and pressure sensing via mechanoluminescence. Finally, directions for future research are given.

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Extending the afterglow in CaAl_2O_4:Eu,Nd persistent phosphors by electron beam annealing

Cited by 37 publications

References 29 publications

Revealing trap depth distributions in persistent phosphors

Revealing trap depth distributions in persistent phosphors

Recent progress in understanding the persistent luminescence in SrAl₂O₄:Eu,Dy

Persistent luminescence in nitride and oxynitride phosphors: A review

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Extending the afterglow in CaAl_2O_4:Eu,Nd persistent phosphors by electron beam annealing

Cited by 37 publications

References 29 publications

Revealing trap depth distributions in persistent phosphors

Revealing trap depth distributions in persistent phosphors

Recent progress in understanding the persistent luminescence in SrAl2O4:Eu,Dy

Persistent luminescence in nitride and oxynitride phosphors: A review

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Product

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Recent progress in understanding the persistent luminescence in SrAl₂O₄:Eu,Dy