Structure, Crystallographic Sites, and Tunable Luminescence Properties of Eu2+ and Ce3+/Li+-Activated Ca1.65Sr0.35SiO4 Phosphors

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• 作者：Zhiguo Xia ; Shihai Miao ; Mingyue Chen ; Maxim S. Molokeev ; Quanlin Liu
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：August 17, 2015
• 年：2015
• 卷：54
• 期：16
• 页码：7684-7691
• 全文大小：651K
• ISSN：1520-510X

文摘

Eu²⁺ and Ce³⁺/Li⁺ singly doped and Eu²⁺/Ce³⁺/Li⁺-codoped Ca_1.65Sr_0.35SiO₄ phosphors have been synthesized by a solid-state reaction method. The crystal structure was determined by Rietveld refinement to verify the formation of the 伪_L^{鈥?/sup>-Ca₂SiO₄ phase with the Sr addition into Ca₂SiO₄, and the preferred crystallographic positions of the Eu2+ and Ce3+/Li+ ions in Ca_1.65Sr_0.35SiO₄ were analyzed based on a comparison of the unit-cell volumes and the designed chemical compositions of undoped isostructural compounds Ca_(2鈥?i>x)Sr_xSiO₄ (x = 0.25, 0.35, 0.45, 0.55 and 0.65). Ce3+/Li+ singly activated Ca_1.65Sr_0.35SiO₄ phosphors exhibit strong absorption in the range of 250鈥?50 nm and a blue emission peak centered at about 465 nm. When Eu2+ ions are codoped, the emission colors of Ca_1.65Sr_0.35SiO₄:Ce3+,Li+,Eu2+ phosphors under the irradiation of 365 nm can be finely tuned from blue to green through the energy transfer from Ce3+ to Eu2+. The involved energy-transfer process between Ce3+ and Eu2+ and the corresponding mechanism are discussed in detail. The reported Ca_1.65Sr_0.35SiO₄:Ce3+,Li+,Eu2+ phosphor might be a candidate for color-tunable blue-green components in the fabrication of near-ultraviolet-pumped white-light-emitting diodes (WLEDs).}