Photoluminescence Properties and Energy Transfer in Eu2+-Yb2+ Codoped SrSi2O2N2 Oxynitride Phosphor
Photoluminescence Properties and Energy Transfer in Eu2+-Yb2+ Codoped SrSi2O2N2 Oxynitride Phosphor
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DOI：
10.1149/2.003202jes
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发表时间：
2011
影响因子：
3.9
通讯作者：
J. Ruan;R. Xie;N. Hirosaki;T. Takeda
中科院分区：
文献类型：
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作者：
J. Ruan;R. Xie;N. Hirosaki;T. Takeda
制备了Eu 2+ -Yb 2+共掺SrSi 2 O2 N2荧光粉，并与单掺Eu 2+和单掺Yb 2+的样品进行了比较研究。研究了Yb 2+离子浓度、激发波长、温度等因素对发光性能的影响。与单掺Yb 2+样品相比，Eu 2+ -Yb 2+共掺样品的发光强度、荧光寿命、量子效率和热稳定性都有所提高。Eu 2+离子与Yb 2+离子之间的能量传递是导致荧光增强的主要原因。最高能量转换效率估计为91.9%。在Eu 2+ -Yb 2+共掺杂样品中还观察到了半峰宽约为170 nm的宽带黄光发射，这可能是Eu 2+和Yb 2+离子的共激发所致。由于SrSi 2 O2 N2：Eu 2+ /Yb 2+荧光粉在大功率LED（> 1 W/mm 2）工作温度下的量子效率太低，且发光会发生明显的热猝灭，因此可能仅适用于小功率高Ra pc白光LED。
Eu 2+ -Yb 2+ codoped SrSi 2 O 2 N 2 phosphors were prepared and their photoluminescence properties were investigated in comparison with the single Eu 2+ -doped and the single Yb 2+ -doped samples. Their photoluminescence properties were investigated as the factors of Yb 2+ ion concentration, excitation wavelength, and temperature. Compared to the single Yb 2+ -doped sample, the Eu 2+ -Yb 2+ codoped sample showed improved emission intensity, fluorescence lifetime, quantum efficiency, and thermal stability. An efficient energy transfer process from Eu 2+ ions to Yb 2+ ions was proposed to be responsible for the enhancement. The highest energy transfer efficiency was estimated to be 91.9%. A broadband yellow emission with full width at half maximum of ∼ 170 nm was also observed in the Eu 2+ -Yb 2+ codoped sample, which could be assigned to the co-excitation of Eu 2+ and Yb 2+ ions. In view of too low quantum efficiency and the considerable thermal quenching of the emission at the operation temperature of high-power LED (> 1 W/mm 2 ), the SrSi 2 O 2 N 2 :Eu 2+ /Yb 2+ phosphor might be only potential for low-power high Ra pc-white LED.