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

Eu<sup>2+sup> and Ce<sup>3+sup>/Li<sup>+sup> singly doped and Eu<sup>2+sup>/Ce<sup>3+sup>/Li<sup>+sup>-codoped Ca<sub>1.65sub>Sr<sub>0.35sub>SiO<sub>4sub> 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<sub class="stack">Lsub><sup class="stack">鈥?/sup>-Ca<sub>2sub>SiO<sub>4sub> phase with the Sr addition into Ca<sub>2sub>SiO<sub>4sub>, and the preferred crystallographic positions of the Eu<sup>2+sup> and Ce<sup>3+sup>/Li<sup>+sup> ions in Ca<sub>1.65sub>Sr<sub>0.35sub>SiO<sub>4sub> were analyzed based on a comparison of the unit-cell volumes and the designed chemical compositions of undoped isostructural compounds Ca<sub>(2鈥?i>x)sub>Sr<sub>xsub>SiO<sub>4sub> (x = 0.25, 0.35, 0.45, 0.55 and 0.65). Ce<sup>3+sup>/Li<sup>+sup> singly activated Ca<sub>1.65sub>Sr<sub>0.35sub>SiO<sub>4sub> phosphors exhibit strong absorption in the range of 250鈥?50 nm and a blue emission peak centered at about 465 nm. When Eu<sup>2+sup> ions are codoped, the emission colors of Ca<sub>1.65sub>Sr<sub>0.35sub>SiO<sub>4sub>:Ce<sup>3+sup>,Li<sup>+sup>,Eu<sup>2+sup> phosphors under the irradiation of 365 nm can be finely tuned from blue to green through the energy transfer from Ce<sup>3+sup> to Eu<sup>2+sup>. The involved energy-transfer process between Ce<sup>3+sup> and Eu<sup>2+sup> and the corresponding mechanism are discussed in detail. The reported Ca<sub>1.65sub>Sr<sub>0.35sub>SiO<sub>4sub>:Ce<sup>3+sup>,Li<sup>+sup>,Eu<sup>2+sup> phosphor might be a candidate for color-tunable blue-green components in the fabrication of near-ultraviolet-pumped white-light-emitting diodes (WLEDs).