Role of B2O3 on the phase stability and long phosphorescence of SrAl2O4:Eu, Dy

Nag, Abanti; Kutty, T.R.N.

doi:10.1016/s0925-8388(03)00009-4

Cited by 258 publications

(192 citation statements)

References 12 publications

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“…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]. * These authors contributed equally.…”

Section: Introductionmentioning

confidence: 99%

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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Section: Introductionmentioning

confidence: 99%

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

2014

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“…The optimum ratio of reactants can make the combustion reaction more complete and benefit the formation of crystalline particles. The minor amount of H 3 BO 3 was introduced as flux in the experiment, since it was proved to be effective in stimulating host-lattice formation and grain growth in some studies [21][22][23][24]. The molar ratio of boric acid to calcium nitrate was varied from 0 to 0.12.…”

Section: Resultsmentioning

confidence: 99%

Luminescent properties of Li2 (Ca0.99, Eu0.01) SiO4: B3+ particles as a potential bluish green phosphor for ultraviolet light-emitting diodes

Yao

Chen

2007

Open Physics

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In our study, the 1% mol Eu2+ doped Li2CaSiO4: B3+ phosphors were prepared by the combustion method as fluorescent material for ultraviolet, light-emitting diodes (UV-LEDs) used as a light source. The properties of Li2 (Ca0.99, Eu0.01) SiO4: B3+ phosphors with urea concentration, doping boric acid and a series of initiating combustion temperature were investigated. The crystallization and particle sizes of Li2 (Ca0.99, Eu0.01) SiO4: B3+ has been investigated by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Luminescence measurements showed that the phosphors can be efficiently excited by UV to the visible region, and exhibited bluish green light with a peak of 480 nm. The results showed that the boric acid was effective in improving the luminescence intensity of Li2 (Ca0.99, Eu0.01) SiO4: B3+ and the optimum molar ratio of boric acid to calcium nitrate was about 0.06. The optimized phosphors Li2 (Ca0.99, Eu0.01) SiO4: B0.063+ showed 180% improved emission intensity compared with that of the Li2 (Ca0.99, Eu0.01) SiO4 phosphors under ultraviolet (λex =287 nm) excitation.

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“…19) In particular, the solid solubility limit has been reported by Y. Yu et al 21) They showed the accurate analysis for the main peak shifts for the general solid state reaction and the amount of the solid solubility limit of around 3 wt % of boron. They concluded that additional boron caused the formation of the impurity phases such as the SrB 2 O 4 and SrAl 4 O 7 .…”

Section: Effect Of B 2 O 3 Addition On Pl Propertiesmentioning

confidence: 93%