Fluorescent Properties of Alkaline Earth Aluminates of the Type MAl[sub 2]O[sub 4] Activated by Divalent Europium

Palilla, Frank C.; Levine, Albert K.; Tomkus, Maija R.

doi:10.1149/1.2411379

Cited by 349 publications

(183 citation statements)

References 5 publications

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“…The emission spectrum is due to 4f 6 5d→4f 7 transition of Eu 2+ . The PL spectra are in good agreement with the results reported in the literature [11,35,36].…”

Section: Prediction Of Eu 2+ Levels From Ce 3+supporting

confidence: 91%

“…BaAl 2 O 4 :Eu 2+ ,Dy 3+ [8] and BaAl 2 O 4 :Eu 2+ ,Nd 3+ [9] also exhibit long lasting phosphorescence (LLP) properties. Eu 2+ doped BaAl 2 O 4 and SrAl 2 O 4 could be promising phosphor materials for plasma display panel (PDP) application [10,11]. SrAl 2 O 4 is one of the foremost promising host materials for fluorescent lamp, light emitting diodes, and persistent luminescent materials [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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d–f luminescence of Ce3+ and Eu2+ ions in BaAl2O4, SrAl2O4 and CaAl2O4 phosphors

Gedekar¹,

Wankhede²,

Moharil

et al. 2017

J Adv Ceram

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“…The emission spectrum is due to 4f 6 5d→4f 7 transition of Eu 2+ . The PL spectra are in good agreement with the results reported in the literature [11,35,36].…”

Section: Prediction Of Eu 2+ Levels From Ce 3+supporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

d–f luminescence of Ce3+ and Eu2+ ions in BaAl2O4, SrAl2O4 and CaAl2O4 phosphors

Gedekar¹,

Wankhede²,

Moharil

et al. 2017

J Adv Ceram

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show abstract

“…At room temperature, the afterglow of SrAl 2 O 4 :Eu,Dy lasts for several hours, which is the result of the gradual, thermally assisted release of trapped charges in the phosphor. This long afterglow is in contrast to the duration of only a few minutes for the variant without codopant [13]. Even longer afterglow durations can be obtained by tuning the synthesis conditions, e.g., by boron addition [14].…”

Section: Introductionmentioning

confidence: 90%

Trapping and detrapping inSrAl2O4:Eu,Dypersistent phosphors: Influence of excitation wavelength and temperature

2014

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SrAl 2 O 4 :Eu,Dy is presumably the best known persistent luminescent phosphor. At room temperature, its green emission remains visible for hours after switching off the excitation. It is known that upon lowering the temperature of the phosphor a second photoluminescence emission band arises in the blue part of the visible spectrum, although its origin is still the subject of discussion. In this paper we thoroughly study the origin of both emission bands in SrAl 2 O 4 :Eu,Dy and we attribute this to europium ions substituting for the two different Sr sites in the phosphor's monoclinic host lattice. The photoluminescence properties, the thermal quenching behavior, and photoluminescence lifetime of both emission bands are investigated. A lanthanide energy level scheme is constructed for both sites. Using an integrated approach, i.e., combining charging, afterglow, and thermoluminescence measurements in the same run, we study the charging or trap filling processes in SrAl 2 O 4 :Eu,Dy upon excitation with site selective excitation wavelengths and at different temperatures. We show that trap filling is a thermally activated process when the green emitting center is excited at 435 nm.Furthermore, we also demonstrate that the distribution of filled traps after charging depends strongly on the excitation wavelength and thus on which Eu 2+ center has been excited. This suggests trapping of the electron close to the ionized Eu 2+ ion, without full delocalization to the conduction band during the trapping process. Finally, the quantum efficiency of the persistent luminescence is estimated at 65 (+/−10)%.

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“…This material, closely related to the aforementioned SrAl 2 O 4 :Eu,Dy, has a long-lasting afterglow in the violet-blue region of the visible spectrum. Its luminescent properties were first described by Blasse and Bril 49 and Palilla et al 50 in 1968, but in 1996 Matsuzawa et al mentioned its persistent luminescence. 2 An afterglow duration of up to 10 h is mentioned in literature.…”

Section: Trap Depth Distribution In Caal 2 O 4 :Eundmentioning

confidence: 95%

“…The location and shape of the spectrum is consistent with previous reports. 49,50,66 The decay of the afterglow after 5 min excitation by 365 nm radiation is shown in Fig. 6.…”

Section: Emission and Afterglowmentioning

confidence: 99%

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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Fluorescent Properties of Alkaline Earth Aluminates of the Type MAl[sub 2]O[sub 4] Activated by Divalent Europium

Cited by 349 publications

References 5 publications

d–f luminescence of Ce3+ and Eu2+ ions in BaAl2O4, SrAl2O4 and CaAl2O4 phosphors

d–f luminescence of Ce3+ and Eu2+ ions in BaAl2O4, SrAl2O4 and CaAl2O4 phosphors

Trapping and detrapping inSrAl2O4:Eu,Dypersistent phosphors: Influence of excitation wavelength and temperature

Revealing trap depth distributions in persistent phosphors

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