纳米晶ZrO_2∶Dy^(3+)的光致发光和能量传递性质

Photoluminescent Properties and Energy Transfer Processes of Nanocrystalline ZrO_2∶Dy^(3+)

研究了Dy3+离子掺杂的ZrO2纳米粉体的光致发光性质。观测到Dy3+离子的室温强特征发射和浓度猝灭现象以及基质ZrO2与Dy3+离子之间的能量传递过程。发现了煅烧温度对样品的晶相有明显的影响,随着煅烧温度的变化,晶相也随之改变。晶相的改变使样品的荧光发射产生较大的差异,并观测到两个发射中心。通过对荧光强度与激活离子Dy3+离子浓度的关系研究发现,Dy3+离子在纳米ZrO2基质中存在浓度猝灭现象,最佳掺杂浓度取决于ZrO2基质的晶相,不同晶相导致不同的猝灭浓度,当基质晶相表现为四方相时,猝灭浓度为0.5%,而基质晶相为混合相时,猝灭浓度为1%。能量传递也依赖于样品的晶相。当煅烧温度为950℃时能量传递效果最好,并且从微观结构上给出了解释基质与Dy3+离子之间的能量传递的模型。

The photoluminescent properties of nanocrystalline ZrO2： Dy^3＋ powders were studied in this paper. We observed the room temperature sharp characteristic emission of Dy^3＋ , its concentration quenching and the energy transfer between the nanocrystalline ZrO2 host and the rare earth ion Dy^3＋. The sintering temperatures gave appreciable influence on the crystalline phases of the nanocrystalline ZrO2. As the sintering temperature was changed, the crystalline phase was also changed, which made the characteristic emission of Dy^3＋ obvious different. It is shown that there exist two emission centers for the rare earth ion Dy^3＋ which occupy different crystalline phases produced by calcining samples at different temperatures. The studies on the effect of the doped Dy^3＋ concentration on the fluorescence emission intensity show that there exists the concentration quenching phenomena of the rare earth ion Dy^3＋ in the nanocrystalline ZrO2 host. The optimum doped concentration depends on the crystalline phase of the host. Different crystalline phases cause different quenching concentration. The optimum concentration for the luminescence Dy^3＋ is determined to be 0.5% for the tetragonal structure and 1% for the mixture crystalline phases. The energy transfer process also depends on the crystalline phase of the host. The energy transfer efficiency is the most highest for the 950 ℃ sample. A model for microscopically explaining the energy transfer processes between the nanocrystalline ZrO2 host and Dy^3＋ was given.