Blue Emitting Ca8La2(PO4)6O2:Ce3+/Eu2+ Phosphors with High Color Purity and Brightness for White LED: Soft-Chemical Synthes

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• 作者：Mengmeng Shang ; Guogang Li ; Dongling Geng ; Dongmei Yang ; Xiaojiao Kang ; Yang Zhang ; Hongzhou Lian ; Jun Lin
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：May 10, 2012
• 年：2012
• 卷：116
• 期：18
• 页码：10222-10231
• 全文大小：577K
• 年卷期：v.116,no.18(May 10, 2012)
• ISSN：1932-7455

文摘

Ce³⁺ and/or Eu²⁺ activated Ca₈La₂(PO₄)₆O₂ (CLPA) oxyapatite blue phosphors have been prepared via a Pechini-type sol鈥揼el process. X-ray diffraction (XRD), photoluminescence (PL) spectra, absolute quantum yield, as well as lifetimes were utilized to characterize samples. The emission of Ce³⁺ and Eu²⁺ ions at different lattice sites has been identified and discussed. The CLPA:0.04Ce³⁺ phosphor exhibits bright blue emission with higher quantum yield (67%) and excellent CIE coordinates (x = 0.160, y = 0.115) under UV excitation, and the CLPA:0.05Eu²⁺ phosphor also exhibits blue emission with CIE coordinates (0.187, 0.164). The energy transfer from Ce³⁺ to Eu²⁺ in CLPA:Ce³⁺/Eu²⁺ phosphors has been validated and demonstrated to be a resonant type via a dipole鈥揹ipole mechanism. The critical distance (R_c) of Ce³⁺ to Eu²⁺ ions in CLPA was calculated (by the spectral overlap method) to be 26.67 脜. The quantum yields of Ce³⁺ and Eu²⁺ coactivated CLPA phosphors are enhanced compared with that of Eu²⁺ activated samples due to energy transfer. The CIE coordinates of CLPA:0.04Ce³⁺, 0.02Eu²⁺ are (0.179, 0.169). The corresponding luminescence and energy transfer mechanisms have been proposed in detail. These blue phosphors might be promising for use in pc-white LEDs.