Color-Tunable Luminescence and Energy Transfer Properties of Ca9Mg(PO4)6F2:Eu2+, Mn2+ Phosphors for UV-LEDs

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• 作者：Kai Li ; Dongling Geng ; Mengmeng Shang ; Yang Zhang ; Hongzhou Lian ; Jun Lin
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 22, 2014
• 年：2014
• 卷：118
• 期：20
• 页码：11026-11034
• 全文大小：558K
• 年卷期：v.118,no.20(May 22, 2014)
• ISSN：1932-7455

文摘

Eu²⁺-, Mn²⁺-activated Ca₉Mg(PO₄)₆F₂ (CMPF) phosphors with blue to yellow color-tunable emission properties have been synthesized via high-temperature solid-state reaction method. The crystal structure of Ca₉Mg(PO₄)₆F₂ has been identified by Rietveld refinement. The different crystallographic sites of Eu²⁺ in CMPF:Eu²⁺ phosphors have been confirmed by virtue of their fluorescence decay lifetimes. The Eu²⁺-activated CMPF phosphors exhibit broad excitation spectra from 200 to 420 nm (which matches well with the UV-based LED chips) and emission spectra from 380 to 580 nm centered at 454 nm. Energy transfer from Eu²⁺ to Mn²⁺ ions in Eu²⁺, Mn²⁺codoped CMPF samples is possible because of the spectral overlap between Eu²⁺ emission and Mn²⁺ excitation spectra, and the constant fall of fluorescence decay lifetimes of Eu²⁺ ion with increasing Mn²⁺ concentration demonstrates the occurrence of it, which provides the color-tunable emission from blue to yellow through adjusting Mn²⁺ concentration. The energy transfer mechanism between Eu²⁺ and Mn²⁺ ions is verified to be electric dipole鈥搎uadrupole interaction by analyzing the experimental results. The critical distance between them calculated by concentration quenching (14.57 脜) and spectral overlap methods (14.90 脜) are consistent, which testifies the energy transfer mechanism above from Eu²⁺ to Mn²⁺ is appropriate. These results show CMPF:Eu²⁺, Mn²⁺ phosphors could be anticipated for UV-pumped white-light-emitting diodes (wLEDs).