Luminescence Properties and Energy‐Transfer Behavior of a Novel and Color‐Tunable LaMgAl11O19:Tm3+, Dy3+ Phosphor for White Light‐Emitting Diodes |
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| Authors: | Xin Min Minghao Fang Zhaohui Huang Yan'gai Liu Chao Tang Xiaowen Wu |
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| Affiliation: | Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing, China |
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| Abstract: | Novel LaMgAl11O19:Tm3+, Dy3+ phosphors were prepared utilizing a high‐temperature solid‐state reaction method. The phase formation, luminescence properties, energy‐transfer mechanism from the Tm3+ to the Dy3+ ions, the thermal stability, and CIE coordinates were investigated. When excited at 359 nm, the LaMgAl11O19: xTm3+ phosphors exhibit strong blue emission bands at 455 nm. After codoping with Dy3+ and excitation at 359 nm, the LaMgAl11O19:0.03Tm3+, yDy3+ phosphors emitted white light consisting of the characteristic emission peaks of Tm3+ and Dy3+. The Dy3+ emission intensity increased with the Dy3+ concentration due to the energy transfer from Tm3+ to Dy3+, and concentration quenching due to the high Dy3+ doping concentration (y = 0.1 mol) did not occur. The calculation of the CIE coordinates of the LaMgAl11O19:Tm3+, yDy3+ phosphors revealed the tunability of the emission color from blue to bluish‐white and to white by changing the excitation wavelength and the doping concentration. An energy transfer from Tm3+ to Dy3+ by dipole–dipole interaction was confirmed by the decay curve, lifetime, and energy‐transfer efficiency measurements. When excited at 359 nm, the LaMgAl11O19:Tm3+, Dy3+ phosphor also showed good thermal stability, suggesting that it can be used in white LEDs excited by a GaN‐based ultraviolet LED. |
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