CAO Jian, ZHANG Xia, HAO Zhen-dong, ZHANG Jia-hua. NaGdF<sub>4</sub>∶Yb<sup>3+</sup>,Ho<sup>3+</sup> and GdF<sub>3</sub>∶Yb<sup>3+</sup>,Ho<sup>3+</sup> Nanocrystals: Controlled Synthesis and Morphology Dependent Upconversion Luminescence[J]. Chinese Journal of Luminescence, 2011,32(12): 1233-1237
CAO Jian, ZHANG Xia, HAO Zhen-dong, ZHANG Jia-hua. NaGdF<sub>4</sub>∶Yb<sup>3+</sup>,Ho<sup>3+</sup> and GdF<sub>3</sub>∶Yb<sup>3+</sup>,Ho<sup>3+</sup> Nanocrystals: Controlled Synthesis and Morphology Dependent Upconversion Luminescence[J]. Chinese Journal of Luminescence, 2011,32(12): 1233-1237DOI:
nanocrystals were successfully prepared by hydrothermal method. The samples were characterized by X-ray powder diffraction (XRD)
scanning electron microscopy (SEM) and luminescence spectra. The crystal structure and morphology can be well controlled by adjusting the molar ratio of
n
(F
-
)∶
n(Ln
3+
)
the value of pH and the molar ratio of
n
(Citrate)∶
n(Ln)
. The hexagonal NaGdF
4
∶Yb
3+
Ho
3+
and GdF
3
∶Yb
3+
Ho
3+
samples exhibit green(541 nm)and red(647 nm)emissions under 980 nm excitation
which are assigned to the transition of
5
F
4
5
S
2
5
I
8
and
5
F
5
5
I
8
in Ho
3+
respectively. It was found that the upconversion efficiency of the hexagonal prism and flake NaGdF
4
∶Yb
3+
Ho
3+
samples are much stronger than that of GdF
3
∶Yb
3+
Ho
3+
samples
but the spherical NaGdF
4
∶Yb
3+
Ho
3+
samples are weaker than GdF
3
∶Yb
3+
Ho
3+
samples. This indicates that the upconversion efficiency of hexagonal NaGdF
4
∶Yb
3+
Ho
3+
samples are greatly impacted by the different size and crystalline for different morphology.
关键词
Keywords
references
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