Eu2+luminescence in strontium aluminates (original) (raw)
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Eu 2+ luminescence in strontium aluminates
Phys. Chem. Chem. Phys., 2015
The luminescence properties of Eu2+ doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6.
Effect of boron substitution on the preparation and luminescence of Eu2+ doped strontium aluminates
Journal of Alloys and Compounds, 2004
A series of monoclinic strontium aluminates, SrAl 2−x B x O 4 :Eu 2+ (0 ≤ x ≤ 0.3), were prepared by a solid state reaction. The effect of boron on the preparation, structure and luminescence was studied by thermoanalytical, X-ray powder diffraction (XPD), UV excited as well as thermoluminescence (TL) methods. Boron decreased clearly the reaction threshold temperature but concentration was not found important. Boron decreased also the amount of impurities. The monoclinic structure remained the same irrespective of the boron content. No Al-B solid solution was formed. The luminescence band position, shape, and width were not changed as a function of the boron content. The UV excited luminescence intensity was enhanced but persistent luminescence suppressed when the boron concentration increased. The thermoluminescence peak shifted slightly towards lower temperatures and the TL intensity was suppressed by increasing boron concentration maybe due to the modification of trap concentration and depth.
Journal of Non-crystalline Solids, 2009
Strong blue-green light emitting Eu doped SrAl 2 O 4 phosphor was synthesized by a low-temperature initiated, self-propagating and gas producing combustion process in a very short time (<5 min). The prepared powder was characterized by X-ray diffraction, Fourier-transform infrared spectrometry and scanning electron microscopy. The excitation spectrum shows a peak at 397 nm. Upon excitation at 397 nm, the emission spectrum exhibits a well defined broad band with maximum at 493 nm corresponding to 4f 6 5d ? 4f 7 transition. Electron paramagnetic resonance (EPR) measurements at X-band showed low field signals due to Eu 2+ ions in SrAl 2 O 4 :Eu.
Journal of Luminescence, 2019
On the effects of milling and thermal regeneration on the luminescence properties of Eu 2þ and Dy 3þ doped strontium aluminate phosphors Viktor Havasi a , D� avid T� atrai b , G� abor Szab� o b,c , Erika Varga d , Andr� as Erd} ohelyi d , Gy€ orgy Sipos e , Zolt� an K� onya a, f , � Akos Kukovecz a, *
Developments in Eu+2-Doped Strontium Aluminate and Polymer/Strontium Aluminate Composite
Advances in Polymer Technology, 2014
The discovery of rare earth based phosphors in 1960s started a new era of luminescence. In comparison with sulfide-based phosphors, strontium aluminates received worldwide acceptance because of their chemical stability and good luminescent properties. The SrAl x O y :Eu 2+ ,Dy 3+ phosphors excited by UV or visible light emit phosphorescence in the blue-green region after the excitation source has been removed, and the phosphorescence last for more than 15 h. The major disadvantage of SrAl x O y :Eu 2+ ,Dy 3+ phosphors is that they are prone to hydrolysis and their luminescent properties gradually deteriorate. The dispersion of these phosphors in a waterproof polymer matrix is an alternative method reported for retaining their luminescent properties. The review extensively deals with strontium aluminate based luminescent materials, the mechanism of luminescence, their synthesis techniques, and different mixing procedures to prepare polymer/strontium aluminate composites. Different methods to improve the dispersion of the strontium aluminate in the polymer matrix are also outlined.
Mechanisms of persistent luminescence in Eu2+, RE3+ doped alkaline earth aluminates
Journal of Luminescence, 2001
Persistent luminescence of Eu 2+ doped calcium aluminate, CaAl 2 O 4 : Eu 2+ , was studied under UV-and visible illumination. Broad band luminescence was observed in the blue region (l max ¼ 440 nm) due to the 4f 6 5d 1 -4f 7 transition of Eu 2+ . The threshold for the visible excitation was found at about 530 nm, which is not high enough in energy to create a monovalent Eu + ion required by the mechanisms presented previously. The new mechanism proposed involves the excited state absorption of two 530 nm photons via deep traps followed by trapping of electrons in shallow traps. The persistent luminescence is observed after a temperature controlled electron-hole recombination and subsequent energy transfer to the Eu 2+ luminescent center. r
Luminescence behaviour of rare earth doped alkaline earth aluminates prepared by the halide route
Materials Letters, 2002
The fluorescence and long persistent phosphorescence behaviour of alkaline earth aluminates of the type MAl 2 O 4 (M = Ba, Sr or Ca) doped with rare earth ions has been extensively studied in the literature. These phosphors are usually prepared using their oxides as the starting materials and employing temperatures in excess of 1000 jC. In this paper, we report the possibility of synthesizing the alkaline earth aluminates starting from the alkaline earth halides. The operating temperatures are around 900 jC, yet single-phase materials with high luminescence output have been realized. D
Effect of Al/Sr ratio on the luminescence properties of SrAl2O4:Eu2+, Dy3+ phosphors
Recent studies have brought out many phosphors like Eu 2+ , Dy 3+ -doped alkaline earth aluminates. The trivalent Dy 3+ ions as co-dopants greatly enhance the duration and intensity of persistent luminescence. These phosphors show excellent properties, such as high quantum efficiency, long persistence of phosphorescence, good stability and suitable color emission.
Advances in Science and Technology, 2010
The detailed preparation process of Eu 2+ and Dy 3+ ion co-doped phosphor powders in Sr 4 Al 14 O 25 :Eu 2+ /Dy 3+ phosphor system with bluish-green long afterglow produced by solid state reaction method under reducing atmosphere is here reported. X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis were made to assign the effects of Eu and Dy ions on the luminescent properties of the synthesized phosphors, which were determined by measuring the photoluminescence spectra. The maximum emission intensity of these phosphors under excitation was investigated. As a result, the relevant values were obtained from the phosphorescent pigment with 0.21% and 0.05% molar percent of