National Key laboratory of Materials Behaviours & Evaluation Technology in Space Environments, Harbin Institute of Technology, Harbin, 150001, PR China.
Nanoscale. 2012 Feb 7;4(3):779-84. doi: 10.1039/c1nr11365h. Epub 2011 Dec 12.
β-NaGdF(4) : Yb(3+)/Er(3+) nanoparticles (NPs) codoped with Li(+) ions were prepared for the first time via a thermal decomposition reaction of trifluoroacetates in oleylamine. The influence of site occupancy of Li(+) on the upconversion emission of β-NaGdF(4) : Yb(3+)/Er(3+) NPs was investigated in detail. The upconversion emission intensity was significantly enhanced by introducing different concentrations of Li(+) ions. In contrast to lithium-free β-NaGdF(4) : Yb(3+)/Er(3+), the green and red UC emission intensities of the NPs codoped with 7 mol% Li(+) ions were enhanced by about 47 and 23 times, respectively. The luminescence enhancement should be attributed to the distortion of the local asymmetry around Er(3+) ions. The mechanisms for the enhancement of upconversion emission were discussed. In addition, it was found in our research work that β-NaGdF(4) : Yb(3+)/Er(3+) NPs exhibited paramagnetic features at room temperature and the magnetization was slightly increased by introducing Li(+) ions.
首次通过三氟乙酸盐在油胺中的热分解反应制备了 Li(+)掺杂的β-NaGdF(4)：Yb(3+)/Er(3+)纳米粒子(NPs)。详细研究了 Li(+)占据位置对β-NaGdF(4)：Yb(3+)/Er(3+) NPs上转换发射的影响。通过引入不同浓度的 Li(+)离子，上转换发射强度显著增强。与无锂的β-NaGdF(4)：Yb(3+)/Er(3+)相比，掺杂 7 mol% Li(+)离子的 NPs 的绿光和红光上转换发射强度分别增强了约 47 和 23 倍。发光增强归因于 Er(3+)离子周围局部不对称性的扭曲。讨论了增强上转换发射的机制。此外，在我们的研究工作中发现，β-NaGdF(4)：Yb(3+)/Er(3+) NPs 在室温下表现出顺磁特征，并且通过引入 Li(+)离子略微增加了磁化强度。
