Temperature Quenching of Yellow Ce3+ Luminescence in YAG:Ce
Temperature Quenching of Yellow Ce3+ Luminescence in YAG:Ce
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DOI：
10.1021/cm8030768
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发表时间：
2009-05-26
影响因子：
8.6
通讯作者：
Meijerink, Andries
中科院分区：
文献类型：
--
作者：
Bachmann, Volker;Ronda, Cees;Meijerink, Andries
掺杂有Ce 3+的钇铝石榴石（YAG）是在快速扩展的白色光LED市场中用于将蓝光转换为黄光的磷光体的选择，但是通常认为其具有低的发光猝灭温度。发光猝灭温度是一个重要的参数，特别是在高功率LED中，但令人惊讶的是，没有进行系统的研究来测量和理解YAG：Ce中黄色Ce发光的温度猝灭。本文报道了YAG：Ce的发光温度猝灭。对于宽范围的Ce浓度（0.033%和3.3%之间）的发射强度和发光寿命的温度依赖性的报告。Ce发光的本征猝灭温度很高（>700 K）。在文献中报道的较低的淬火温度解释热激活浓度淬火（高掺杂系统）和温度依赖性的振荡器强度（低掺杂浓度）。此外，高分辨率的光谱报告，它提供洞察的零声子跃迁的位置（20450 cm（-1）），斯托克斯位移（2400 cm（-1）），占主导地位的声子模式的能量（200 cm（-1）），和黄-里斯参数（S = 6）。这些参数进行了比较与从头计算的位置和弛豫在激发5d状态的Ce 3+在YAG中，这可以帮助提供一个更好的理论理解的温度淬火。
Yttrium aluminum garnet (YAG) doped with Ce3+ is the phosphor of choice for the conversion of blue to yellow light in the rapidly expanding market of white light LEDs, but it is generally thought to suffer from a low luminescence quenching temperature. The luminescence quenching temperature is an important parameter, especially in high-power LEDs, but surprisingly no systematic research has been done to measure and understand the temperature quenching of the yellow Ce luminescence in YAG:Ce. Here we report on the luminescence temperature quenching in YAG:Ce. For a wide range of Ce concentrations (between 0.033% and 3.3%) the temperature dependence of the emission intensity and the luminescence lifetimes are reported. The intrinsic quenching temperature of the Ce luminescence is shown to be very high (>700 K). The lower quenching temperatures reported in the literature are explained by thermally activated concentration quenching (for highly doped systems) and the temperature dependence of the oscillator strength (for low doping concentrations). In addition, high-resolution spectra are reported, which provide insight into the position of the zero-phonon transition (20450 cm(-1)), the Stokes shift (2400 cm(-1)), the energy of the dominant phonon mode (200 cm(-1)), and the Huang-Rhys parameter (S = 6). These parameters are compared with ab initio calculations on the position of and relaxation in the excited 5d state of Ce3+ in YAG, which can aid in providing a better theoretical understanding of the temperature quenching.