Selective synthesis of LaF3 and NaLaF4 nanocrystals via lanthanide ion doping
Selective synthesis of LaF3 and NaLaF4 nanocrystals via lanthanide ion doping
复制标题
镧系离子掺杂选择性合成LaF3和NaLaF4纳米晶
DOI：
10.1039/c7tc02362f
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发表时间：
2017-09-21
影响因子：
6.4
通讯作者：
Huang, Wei
中科院分区：
文献类型：
--
作者：
Nie, Li;Shen, Yuxing;Huang, Wei
从一系列化学成分相似的可能性中选择性地获得预期的纳米晶体的能力一直是一个长期的挑战。β-LaF3和β-NaLaF4纳米晶是一种具有良好的物理化学稳定性和低声子能量的基质材料。由于La3+-F-离子键很强，很难形成β-NaLaF4纳米晶，研究了不同稀土离子的掺杂对最终产物形成的影响。实验结果表明，与未掺杂的纯β-LaF3纳米晶相比，Ce3+和Pr3+掺杂对合成的β-LaF4纳米晶没有明显的影响，Nd3+、Sm3+、Eu3+、Gd3+和Tb3+的掺杂导致了纯的β-NaLaF4纳米晶的形成，而Dy3+、Ho3+、Er3+、Tm3+、Yb3+和Lu3+的掺杂只导致了两者的混合。此外，适当的稀土离子掺杂也有助于获得增强的上转换和下转换发光。从纳米晶体生长自由能的观点出发，建立了一个理论模型来解释上述现象。
The capability to selectively obtain expected nanocrystals from a series of possibilities with similar chemical compositions has been a long-term challenge. beta-LaF3 and beta-NaLaF4 nanocrystals are a kind of host material with excellent physical and chemical stability as well as low phonon energy. Since beta-NaLaF4 nanocrystals are difficult to form due to the very strong La3+-F- ionic bond, investigations of the doping effect of different lanthanide ions on the formation of the final product were carried out. The experimental results have indicated that Ce3+ and Pr3+ doping has no obvious effect on the product compared to pure beta-LaF3 nanocrystals without doping, and doping of Nd3+, Sm3+, Eu3+, Gd3+, and Tb3+ leads to the formation of pure beta-NaLaF4 nanocrystals while doping of Dy3+, Ho3+, Er3+, Tm3+, Yb3+, and Lu3+ only results in a mixture of both. What is more, proper lanthanide ion doping can also help in obtaining enhanced up- and downconversion luminescence. A theoretical model from the nanocrystal growth free energy point of view has been developed to explain the above phenomenon.