Formation and characterization of Lu silicate nanoparticles in amorphous SiO2

Kępiński, Leszek; Mączka, Mirosław; Drozd, M.

doi:10.1016/j.jallcom.2006.09.127

Cited by 11 publications

(1 citation statement)

References 41 publications

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“…The appearance of Lu-O (491 and 575 cm −1 ) bands testifies to crystalline lutetium oxide formation onto the SiO 2 particles. A number of absorption bands appear in the FT-IR spectrum of the sample after the annealing at 1200 • C due to lutetium pyrosilicate formation onto the SiO 2 core, namely at 910, 990, 854 cm −1 that corresponds to Si-O stretching vibrations and at 567, 500 cm −1 , which are attributed to the bending vibration of [Si 2 O 7 ] 6− ions in the LPS compound [22,23].…”

Section: Ft-ir Spectroscopymentioning

confidence: 99%

Spherical core–shell structured nanophosphors on the basis of europium-doped lutetium compounds

et al. 2009

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Crystalline Lu(2)O(3):Eu(3+) nanolayers with a europium content from 1 to 10 at.% were immobilized onto amorphous SiO(2) submicrospheres by a sol-gel technique, forming monodisperse SiO(2)/Lu(2)O(3):Eu(3+) core-shell structured nanophosphors. The nanostructure, morphology and composition of the core-shell particles obtained were investigated by transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) techniques. The Lu(2)O(3) nanolayers are found to begin to crystallize on the SiO(2) cores at 500 degrees C and a solid-phase reaction between the Lu(2)O(3) and SiO(2) components occurs at 1000 degrees C. Lu(2)O(3) --> Lu(2)SiO(5) --> Lu(2)Si(2)O(7) phase transitions in the core-shell particles were observed at temperatures ranging from 1000 to 1200 degrees C. Under x-ray excitation, europium-doped core-shell nanophosphors are characterized by effective luminescence in the lambda = 575-725 nm range corresponding to (5)D(0) --> (7)F(J) transitions (J = 0-4) of Eu(3+) ions. It has been shown that the radioluminescence intensity of the heterostructures strongly depends on the annealing temperature, the number of coated layers and the dopant concentration. The radioluminescence of the SiO(2)/Lu(2)O(3):Eu(3+) heterostructures coated with a protective undoped Lu(2)O(3) shell is higher than in the case of the unprotected SiO(2)/Lu(2)O(3):Eu(3+) core-shell phosphors. The possible reasons for such a phenomenon are also discussed.

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Section: Ft-ir Spectroscopymentioning

confidence: 99%

Spherical core–shell structured nanophosphors on the basis of europium-doped lutetium compounds

et al. 2009

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Formation and Characterization of Lu Silicate Nanoparticles in Amorphous SiO₂.

2007

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Formation and Characterization of Lu Silicate Nanoparticles in Amorphous SiO2. -Reaction of nanocrystalline Lu 2 O 3 with amorphous SiO 2 is studied at 600-1200°C using powder XRD, HRTEM, FT-IR, FT-Raman spectroscopy, and Yb 3+ emission spectroscopy. Lu can be dispersed over SiO2 up to a loading corresponding to ca. 10 µmol Lu2O3/m 2 SiO2. At 1000°C formation of crystalline silicate, isomorphous with B-type Ln4[Si3O10][SiO4] (Ln: Dy-Tm), occurs. Emission bands of Yb 3+ , present as contamination in Lu 2 O 3 , are used as convenient tool for the identification of the Lu-phases formed in the samples. -(KEPINSKI*, L.; MACZKA, M.; DROZD, M.; J. Alloys

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