Effect of Al/Sr ratio on the luminescence properties of SrAl₂O₄:Eu²⁺, Dy³⁺ phosphors

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• 作者：Selvin Yeş ; ilay Kaya^a ; ^{selvin.yesilay@gmail.com} ; ^{syesilay@anadolu.edu.tr} ; Erkul Karacaoglu^b ; Bekir Karasu^b
• 关键词：Long persistence phosphorescence ; Strontium aluminates ; Al/Sr ratio ; Crystal
• 刊名：Ceramics International
• 出版年：2012
• 期刊代码：13_02728842
• 类别：ms
• 出版时间：July, 2012
• 卷：38
• 期：5
• 页码：3701-3706
• 文件大小：802 K

摘要

Recent studies have brought out many phosphors like Eu²⁺, Dy³⁺-doped alkaline earth aluminates. The trivalent Dy³⁺ 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.

In this work the effect of Al/Sr ratio on the afterglow and phosphorescence decay properties of Eu²⁺ and Dy³⁺ co-activated strontium aluminates synthesized by a solid-state process has been investigated. The luminescence properties of samples were investigated by means of excitation spectra, emission spectra and X-ray diffraction analysis.

A variety of strontium aluminates, such as SrAl₂O₄, Sr₄Al₂O₇, Sr₃Al₂O₆, Sr₃Al₂(Eu, Dy, Y)O_7.5, Al₅(Eu, Dy, Y)O₁₂, Sr₄Al₁₄O₂₅, SrAl₁₂O₁₉ and (Eu, Dy, Y)AlO₃ have been identified in the samples prepared from starting precursors with Al/Sr mole ratios ranging from 0.44 to 5. The afterglow decay rate was found to be the fastest for sample with Al/Sr ratio of 4.18, in which SrAl₄O₇ phase was dominant. The afterglow decay rate for phosphor with Al/Sr ratio of 2, in which SrAl₂O₄ phase was dominant, was detected to be slow. Moreover, the emission spectra of the samples shift to yellow-green long wavelength from bluish-green-ultraviolet short wave with the increase of Al/Sr ratios resulting from the change in the composition.