Er^(3+)及Er^(3+)/Yb^(3+)掺杂纳米晶CaWO_4的发光性质

Luminescent Properties of Er^(3+) and Er^(3+)/Yb^(3+) Doped Nanocrystalline CaWO_4

利用共沉淀法制备了Er3+掺杂及Er3+/Yb3+共掺杂纳米晶CaWO4发光粉体,室温下观察到Er3+的下转换和上转换特征发射。研究了不同煅烧温度、不同掺杂浓度对Er3+离子特征发射的影响。结果表明:随着煅烧温度的升高,发射强度增强;掺杂浓度的改变,导致了Er3+的浓度猝灭现象,其适宜的掺杂原子数分数为0.6%。同时观测到O-W的电荷迁移态与稀土离子之间的能量传递现象,并给出了能量传递的模型。对Er3+的上转换研究观察到:在976nm激光激发下Yb3+对Er3+的上转换发射起到了很好的敏化作用,两个Yb3+同时将能量以共振方式传递给一个Er3+离子,Er3+、Yb3+共掺杂样品的绿光上转换过程展示了双光子过程。

Both Er3＋ and Er3＋-Yb3＋ codoped CaWO4 nanocrystalline were prepared by chemical co-precipitation method.We characted the crystal structures and the room temperature down-conversion emission and upconversion emission properties of samples with different doping concentrations of Er3 ＋ and sintered at different temperatures,respectively.By comparing the influence of different sintering temperatures and doped concentrations on the characteristic emission of Er3 ＋,it was found that the emission intensity depends on the sintering temperature.The emission intensity increases as the sintering temperature increasing.The effect of the concentration of doped Er3 ＋ on the fluorescence emission intensity shows that the optimum concentration for the luminescence of Er3 ＋ is 0.6%.The energy transfer was observed between the charge transfer state of O-W and the rare earth ion Er3 ＋,and a model for explaining the energy transfer was given.By studing the upconversion emission of Er3 ＋,it was showed that the Yb3 ＋ can promote the upconversion emission of Er3 ＋ under 976 nm excitation by the resonance energy transfer.