Synthesis and tunable luminescence properties of Eu2+ and Tb3+-activated Na2Ca4(PO4)3F phosphors based on energy transfer
Synthesis and tunable luminescence properties of Eu2+ and Tb3+-activated Na2Ca4(PO4)3F phosphors based on energy transfer
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DOI：
10.1016/j.jlumin.2012.10.023
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发表时间：
2013-03
影响因子：
3.6
通讯作者：
Jun Zhou;Z. Xia;Hongpeng You;K. Shen;Mengxia Yang;L. Liao
中科院分区：
文献类型：
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作者：
Jun Zhou;Z. Xia;Hongpeng You;K. Shen;Mengxia Yang;L. Liao
采用高温固相反应法制备了一系列可调色蓝绿色发光的Na2Ca4(PO4)3F:Eu2+，Tb3+荧光粉。它们的发光特性表明，Eu2+离子通过偶极子-四极子机制向Tb3+离子进行了高效的能量转移，Eu2+离子在近紫外区表现出较强的激发带，与近紫外（350 ~ 420nm） LED芯片的主发射带匹配良好，Eu2+和Tb3+离子可以发出特征的蓝绿发射光。通过Eu2+到Tb3+离子的能量转移，适当调整Eu2+与Tb3+掺杂的相对比例，可以实现荧光粉从蓝色到绿色的变化。热猝灭发光结果表明，Na2Ca4(PO4)3F:Eu2+，Tb3+具有良好的热稳定性。这些结果表明，在近紫外区4f-4f吸收效率较低的Tb3+离子，能够以较高的振荡强度对Eu2+进行4f-5d吸收，从而有效地供能，在窄型绿色发光荧光粉中发挥活化剂的作用。所制备的Eu2+ -Tb3 +共掺Na2Ca4(PO4)3F荧光粉在近紫外白光led中具有潜在的应用前景。
A series of color-tunable blue–green emitting Na2Ca4(PO4)3F:Eu2+,Tb3+phosphors were prepared by a high temperature solid-state reaction. Their luminescence properties reveal that there is an efficient energy transfer from Eu2+to Tb3+ions via a dipole–quadrupole mechanism where Eu2+ions exhibit a strong excitation band in near ultraviolet (UV) region, matching well with the dominant emission band of near UV (350–420nm) LED chips, and Eu2+and Tb3+ions can give characteristic blue and green emission light. The varied color of the phosphors from blue to green can be achieved by properly tuning the relative ratio of Eu2+to Tb3+dopant through the energy transfer from Eu2+to Tb3+ions. Thermal quenching luminescence results reveal that Na2Ca4(PO4)3F:Eu2+,Tb3+exhibits good thermal stability. These results demonstrate that Tb3+ion with low 4f–4f absorption efficiency in near UV region can play the role of an activator in narrow green-emitting phosphor through efficient energy feeding by allowing 4f–5d absorption of Eu2+with high oscillator strength. The present Eu2+–Tb3+codoped Na2Ca4(PO4)3F phosphor will have potential application for the near UV white LEDs.