Structural, spectroscopic and photoluminescence studies of LiEu(WO₄)_2−x(MoO₄)_x as a near-UV convertible phosphor

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• 作者：Chuang-Hung Chiu ; Ming-Fang Wang ; Chi-Shen Lee ; Teng-Ming Chen
• 关键词：Phosphors ; LiEu(WO₄)₂₋ ; _x(MoO₄)_x ; Photoluminescence ; LED
• 刊名：Journal of Solid State Chemistry
• 出版年：2007
• 期刊代码：130_00224596
• 类别：ch
• 出版时间：February 2007
• 卷：180
• 期：2
• 页码：619-627
• 文件大小：1345 K

摘要

A series of lithium europium double tungsto-molybdate phosphors LiEu(WO₄)_2−x(MoO₄)_x (x=0, 0.4, 0.8, 1.2, 1.6, 2.0) have been synthesized by solid-state reactions and their crystal structure, optical and luminescent properties were studied. As the molybdate content increases, the intensity of the ⁵D₀→⁷F₂ emission of Eu³⁺ activated at wavelength of 396 nm was found to increase and reach a maximum when the relative ratio of Mo/W is 2:0. These changes were found to be accompanied with the changes in the spectral feature, which can be attributed to the crystal field splitting of the ⁵D₀→⁷F₂ transition. As the molybdate content increases the emission intensity of the 615 nm peak also increases. The intense red-emission of the tungstomolybdate phosphors under near-UV excitation suggests them to be potential candidate for white light generation by using near-UV LEDs. In this study the effect of chemical compositions and crystal structure on the photoluminescent properties of LiEu(WO₄)_2−x(MoO₄)_x is investigated and discussed.