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Monodisperse upconversion GdF3:Yb, Er rhombi by microwave-assisted synthesis.

Wang H, Nann T - Nanoscale Res Lett (2011)

Bottom Line: We have synthesized a variety of monodisperse colloidal GdF3:Yb, Er upconversion nanocrystals with different shape, size, and dopants by microwave-assisted synthesis.Typical upconversion emission from Er3+ was observed.In addition to highly monodisperse spherical particles, we were able to prepare monodispersed rhombic-shaped slices that showed a tendency for self-assembly into stacks.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute Materials for Electronics and Energy Technology (I-MEET), Friedrich Alexander Universität Erlangen-Nürnberg, Marternsstraße 7, 91058, Erlangen, Germany. wang.hai-qiao@ww.uni-erlangen.de.

ABSTRACT
We have synthesized a variety of monodisperse colloidal GdF3:Yb, Er upconversion nanocrystals with different shape, size, and dopants by microwave-assisted synthesis. Typical upconversion emission from Er3+ was observed. In addition to highly monodisperse spherical particles, we were able to prepare monodispersed rhombic-shaped slices that showed a tendency for self-assembly into stacks.

No MeSH data available.


XRD pattern of GdF3 nanocrystals as depicted in Figure 1. Full circle (red): diffraction pattern according to JCPDS-file 012-0788; full square (green): diffraction pattern according to JCPDS-file 045-1460.
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Figure 2: XRD pattern of GdF3 nanocrystals as depicted in Figure 1. Full circle (red): diffraction pattern according to JCPDS-file 012-0788; full square (green): diffraction pattern according to JCPDS-file 045-1460.

Mentions: The XRD pattern of these particles (Figure 2) which shows orthorhombic phase GdF3 was obtained. Almost all the diffraction peaks of the XRD pattern can be assigned, respectively, to the planes of orthorhombic GdF3 crystalline (JCPDS-file 012-0788), as indicated (101), (020), (111), (210), (002), (221), (112), (301), (230), (212) in Figure 2 (red, round dot). However, two more weak diffraction peaks can also be observed at 2θ = 38.7° and 45°, which cannot be assigned to GdF3. We considered that these two weak peaks arose from the diffraction of LiF (JCPDS-file 045-1460) [17]. And it suggests that the Li+ was not only introduced into the expected phosphor GdF3 crystal to replace some Gd3+ sites as impurity but also a few LiF was formed. A further confirmation of a predominant GdF3 lattice can be found by measuring distances of the lattice fringes in the high resolution transmission electron microscopy (HRTEM). Lattice fringes were found with distances of 3.29 and 2.94 Å (cf. Figure 3B), corresponding well to the theoretically calculated distance of the {111} and {210} planes of the orthorhombic-YF3 space group GdF3 (orthorhombic phase JCPDS-file 012-0788), respectively. It is noteworthy that the same XRD patterns were observed for decreased and increased reactant concentrations.


Monodisperse upconversion GdF3:Yb, Er rhombi by microwave-assisted synthesis.

Wang H, Nann T - Nanoscale Res Lett (2011)

XRD pattern of GdF3 nanocrystals as depicted in Figure 1. Full circle (red): diffraction pattern according to JCPDS-file 012-0788; full square (green): diffraction pattern according to JCPDS-file 045-1460.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211330&req=5

Figure 2: XRD pattern of GdF3 nanocrystals as depicted in Figure 1. Full circle (red): diffraction pattern according to JCPDS-file 012-0788; full square (green): diffraction pattern according to JCPDS-file 045-1460.
Mentions: The XRD pattern of these particles (Figure 2) which shows orthorhombic phase GdF3 was obtained. Almost all the diffraction peaks of the XRD pattern can be assigned, respectively, to the planes of orthorhombic GdF3 crystalline (JCPDS-file 012-0788), as indicated (101), (020), (111), (210), (002), (221), (112), (301), (230), (212) in Figure 2 (red, round dot). However, two more weak diffraction peaks can also be observed at 2θ = 38.7° and 45°, which cannot be assigned to GdF3. We considered that these two weak peaks arose from the diffraction of LiF (JCPDS-file 045-1460) [17]. And it suggests that the Li+ was not only introduced into the expected phosphor GdF3 crystal to replace some Gd3+ sites as impurity but also a few LiF was formed. A further confirmation of a predominant GdF3 lattice can be found by measuring distances of the lattice fringes in the high resolution transmission electron microscopy (HRTEM). Lattice fringes were found with distances of 3.29 and 2.94 Å (cf. Figure 3B), corresponding well to the theoretically calculated distance of the {111} and {210} planes of the orthorhombic-YF3 space group GdF3 (orthorhombic phase JCPDS-file 012-0788), respectively. It is noteworthy that the same XRD patterns were observed for decreased and increased reactant concentrations.

Bottom Line: We have synthesized a variety of monodisperse colloidal GdF3:Yb, Er upconversion nanocrystals with different shape, size, and dopants by microwave-assisted synthesis.Typical upconversion emission from Er3+ was observed.In addition to highly monodisperse spherical particles, we were able to prepare monodispersed rhombic-shaped slices that showed a tendency for self-assembly into stacks.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute Materials for Electronics and Energy Technology (I-MEET), Friedrich Alexander Universität Erlangen-Nürnberg, Marternsstraße 7, 91058, Erlangen, Germany. wang.hai-qiao@ww.uni-erlangen.de.

ABSTRACT
We have synthesized a variety of monodisperse colloidal GdF3:Yb, Er upconversion nanocrystals with different shape, size, and dopants by microwave-assisted synthesis. Typical upconversion emission from Er3+ was observed. In addition to highly monodisperse spherical particles, we were able to prepare monodispersed rhombic-shaped slices that showed a tendency for self-assembly into stacks.

No MeSH data available.