The capability to selectively obtain expected nanocrystals from a series of possibilities with similar chemical compositions has been a long-term challenge. β-LaF₃ and β-NaLaF₄ nanocrystals are a kind of host material with excellent physical and chemical stability as well as low phonon energy. Since β-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 β-LaF₃ nanocrystals without doping, and doping of Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, and Tb³⁺ leads to the formation of pure β-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.

中文翻译：

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的LaF的选择性合成₃和NaLaF _4个纳米晶体通过镧系元素离子掺杂

从具有相似化学组成的一系列可能性中选择性地获得预期的纳米晶体的能力一直是长期的挑战。β-的LaF ₃和β-NaLaF _4个纳米晶体是一种主体材料的具有优良的物理和化学稳定性以及低声子能量。由于β-NaLaF _4个纳米晶体由于非常强的La难以形式³⁺ -F ^-离子键，不同的镧系元素离子的最终产品形成的掺杂效果的调查进行了。实验结果表明，铈³⁺和Pr ³⁺相比纯β-的LaF掺杂对产品没有明显的影响₃纳米晶体掺杂没有，和Nd掺杂³⁺，SM ³⁺，铕³⁺，钆³⁺和Tb ³⁺导致纯β-NaLaF形成_4个纳米，而镝掺杂³⁺，何³⁺，尔³⁺，Tm ³⁺，Yb ³⁺和Lu ³⁺仅导致两者的混合。而且，适当的镧系元素离子掺杂也可以帮助获得增强的上转换和下转换发光。已经开发了从纳米晶体生长自由能的观点出发的理论模型来解释上述现象。