Photoluminescence Properties of Eu3+-Doped Glaserite-Type Orthovanadates CsK2Gd[VO4]2

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• 作者：Zhengxu Tao ; Taiju Tsuboi ; Yanlin Huang ; Wei Huang ; Peiqing Cai ; Hyo Jin Seo
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：April 21, 2014
• 年：2014
• 卷：53
• 期：8
• 页码：4161-4168
• 全文大小：518K
• 年卷期：v.53,no.8(April 21, 2014)
• ISSN：1520-510X

文摘

Undoped and Eu³⁺-doped glaserite-type orthovanadates CsK₂Gd_1鈥?i>xEu_x[VO₄]₂ with various Eu³⁺ concentrations of x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 were synthesized via the solid-state reaction. The formation of a single phase compound was verified through the X-ray diffraction studies. The photoluminescence (PL) and PL excitation (PLE) spectra, PL decay curves, and absolute quantum efficiency (QE) were investigated. Unlike the conventional Eu³⁺-doped vanadates, these Eu³⁺-doped samples showed not only several sharp emission lines due to Eu³⁺ but also a broad emission band with a maximum at 530 nm due to the [VO₄]^{3鈥?/sup> host. The intensities of the host and Eu3+ emissions increased when the Eu3+ concentration was increased from x = 0 to x = 0.6 and decreased above x = 0.6. Similar concentration dependence was observed for QE. The host emission, even if in the Eu3+-condensed host of CsK₂Eu(VO₄), was never quenched indicating inefficient energy transfer from the host [VO₄]3鈥?/sup> to Eu3+. This inefficient energy transfer is understood by suppression of the energy transfer by the V鈥擮鈥擡u bond angle deviated from 180掳 and the separation of Eu3+ ions at the Gd3+ site from [VO₄]3鈥?/sup>. Like the 530 nm charge transfer [VO₄]3鈥?/sup> emission, two broad and intense PLE bands with maxima at 330 and 312 nm were observed for the Eu3+ emission. A maximum QE of 38.5% was obtained from CsK₂Gd_1鈥?i>xEu_x[VO₄]₂ (x = 0.6). A white-colored emission was obtained by the combination of the broad 530 nm emission band and the intense sharp lines due to Eu3+ at 590鈥?20 nm.}