外文题目: Understanding Enhanced Upconversion Luminescence in Oxyfluoride Glass-Ceramics Based on Local Structure Characterizations and Molecular Dynamics Simulations
作者: Ali, Mohamed A.; Ren, Jinjun; Liu, Xiaofeng; Qiao, Xvsheng; Qiu, Jianrong
刊名: J. Phys. Chem. C
年: 2017 卷: 121 期: 28 页： 15384--15391
英文关键词:

DOPED CAF2 NANOCRYSTALS; PHONON SIDE-BAND; FLUOROSILICATE GLASSES; RAMAN-SPECTROSCOPY; ENERGY-TRANSFER; NANO-CRYSTALS; NANOPARTICLES; EMISSION; EXCITATION; IONS
英文摘要:
In this Article, large enhancement in upconversion (UC) luminescence was verified in a transparent aluminosilicate glass-ceramics (GCs) containing CaF2 nanocrystals (NCs) codoped with Era(3+) and Yb3+ ions. On the basis of the joint spectroscopic and structural characterizations, we suggest that the precipitation of fluoride NCs is correlated with the preexistence of the fluoride-rich domains in the as-melt glass, which is supported by scanning transmission electron microscopy (STEM) and reproduced by molecular dynamics (MD) simulation. The precipitation of the fluoride NCs starts from a phase-separated as-melt glass consisting of fluorine-rich and oxygen-rich domains, while the spatial distribution of rare earth (RE) ions and the vibration energies of the bonds connecting RE ions remain almost unchanged after crystallization. In the GCs, both the fluoride domain and the oxygen-containing polyhedrons surrounding RE ions experience significant ordering, which may affect the UC emission for both glasses and GCs. We therefore attribute the enhanced UC emissions of the GCs to the long-range structural ordering and the change of site symmetry surrounding RE ions, rather than the preference of RE ions in migrating from fluoride-rich phase to the fluoride NCs. Our results may have strong implications for a better understanding of the enhanced UC emission in similar oxyfluoride GCs.


文献类型: 期刊论文
正文语种: English
收录类别: SCI
DOI: 10.1021/acs.jpcc.7b04599


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