205 resultados para CEF3-TB3

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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CeF3:Tb3+ nanoparticles were successfully prepared by a polyol process using diethylene glycol ( DEG) as solvent. After being coated with dense silica, these CeF3:Tb3+ nanoparticles can be coated with mesoporous silica using nonionic triblock copolymer EO20PO70EO20 ( P 123) as structure-directing agent. The composite can load ibuprofen and release the drug in the PBS. The composite was characterized by X-ray diffraction ( XRD), transmission electron microscopy ( TEM), nitrogen absorption/desorption isotherms, fluorescence spectra, and UV/Vis absorption spectra, respectively.

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CeF3 and CeF3:Tb3+ nanoparticles were prepared by reverse microemulsion with a functional monomer, methyl methacrylate (MMA), as the oil phase, and CeF3:Tb3+/poly (methyl methacrylate) (PMMA) nanocomposites were obtained via polymerization of the MMA monomer. The nanoparticles and nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), low- and high-resolution transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetric analysis (TGA), UV/vis transmission spectra, photoluminescence excitation, and emission spectra and luminescence decays. The well-crystallized CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of 15 nm. They show the characteristic emission of Ce3+ 5d-4f (313 nm, D-2-F-2(5/2); 323 nm, D-2-F-2(7/2)) and Tb3+ D-5(4)-F-7(J) (J = 6-3, with D-5(4)-F-7(5) green emission at 541 nm as the strongest one) transitions, respectively.

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LaF3. CeF3, CeF3:Tb3+, and CeF3:Tb3+ @LaF3 (core-shell) 2D nanoplates have been successfully synthesized by a facile and effective hydrothermal process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. The experimental results indicate that the organic additive, trisodium citrate (Cit(3-)), as a shape modifier has the dynamic effect by adjusting the growth rate of different crystal facets, resulting in forming the anisotropic geometries of the final products. The possible formation mechanisms for different products have been presented. The CeF3, CeF3:Tb3+, and CeF3:Tb3+ @LaF3 (core/shell) nanoplates show characteristic emission of Ce3+ (5d-4f) and Tb3+ (f-f), respectively.

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CeF3: Tb3+ nanoparticles (short pillar-like morphology with an average length and width of 11 and 5 nm, respectively) were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. After being functionalized with a SiO2-NH2 layer, these CeF3: Tb3+ nanoparticles can be conjugated with biotin molecules (activated by thionyl chloride) and further with avidin. The as-formed CeF3: Tb3+ nanoparticles, CeF3: Tb3+ nanoparticles functionalized with amino groups, biotin conjugated amino-functionalized CeF3: Tb3+ nanoparticles and biotinylated CeF3: Tb3+ nanoparticles bonded with avidin were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), UV/vis absorption spectra and luminescence spectra, respectively. The biofunctionalization of the CeF3: Tb3+ nanoparticles has less effect on their luminescence properties, i.e. they still show strong green emission (from Tb3+, with D-5(4) - F-7(5) at 543 nm as the most prominent group), indicative of the great potential for these CeF3: Tb3+ nanoparticles to be used as biological fluorescence probes.

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CeF3, CeF3:Tb3+, and CeF3:Tb3+/LaF3 (core/shell) nanoparticles were prepared by the polyol method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), UV-vis absorption spectra, photoluminescence (PL) spectra, and lifetimes. The results of XRD indicate that the obtained CeF3, CeF3:Tb3+, and CeF3:Tb3+/LaF3 (core/shell) nanoparticles crystallized well at 200 degrees C in diethylene glycol (DEG) with a hexagonal structure. The TEM images illustrate that the CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of 7 nm. The growth of the LaF3 shell around the CeF3:Tb3+ core nanoparticles resulted in an increase of the average size (11 nm) of the nanopaticles as well as in a broadening of their size distribution. These nanocrystals can be well-dispersed in ethanol to form clear colloidal solutions. The colloidal solutions of CeF3 and CeF3:Tb3+ show the characteristic emission of Ce3+ 5d-4f (320 nm) and Tb3+ D-5(4)-F-7(J) (J = 6-3, with D-5(4)-F-7(5) green emission at 542 nm as the strongest one) transitions, respectively. The emission intensity and lifetime of the CeF3:Tb3+/LaF3 (core/shell) nanoparticles increased with respect to those of CeF3:Tb3+ core particles.

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CeF3:Tb3+SOCl2CeF3:Tb3+ CeF3:Tb3+ CeF3:Tb3+ P123CeF3:Tb3+ 24 h NaYF4:Yb3+, Er3+ NaYF4:Yb3+, Er3+ NaYF4:Yb3+, Er3+ P123PVP TMB NaYF4:Yb3+, Er3+ 12 h YVO4:Eu3+ 80 nm43 nmYVO4:Eu3+ 5D0FT-IR XPS Eu3+ (5D0 level) CAPTES

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NdF3 and TbF3 nanoparticles were successfully synthesized via a solvent extraction route using Cynex923 (R3P=O). X-ray diffraction (XRD) study showed that pure hexagonal phase NdF3 and pure orthorhombic phase TbF3 could be obtained under the current synthetic conditions. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observations indicated that as-obtained NdF3 nanoplates have a diameter of 50-80 nm and thickness of 10-20 nm and TbF3 products have sphere morphologies with diameter from 70 to 170 nm. The driving force for the growth of NdF3 nanoplates could be attributed to the hexagonal crystal structure. The luminescence properties of NdF3 and TbF3 nanoparticles were investigated, which indicated that NdF3 nanoparticles showed typical emission at 888,1064, and 1328 nm and TbF3 nanoparticles showed characteristic emission of Tb3+ (f-f).

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Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B-2(0) and the magnetic exchange interaction was studied as temperature approaches to 0 K. The results show that the stabilization energy contributed by Tb3+ is linear with crystal field coefficient B-2(0) approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substances such as TbCo5, Tb2Co17 and Tb2Fe14B compounds.

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Ag nanoparticle embedded NaYF4:0.05Tb center dot chi Ce/ PVP (PVP stands for poly(vinyl pyrrolidone)) composite nanofibers have been prepared by electrospinning. A field emission scanning electron microscope and x-ray diffraction have been utilized to characterize the size, morphology and structure of the as-prepared electrospun nanofibers. Obvious photoluminescence (PL) of NaYF4:0.05Tb center dot 0.05Ce/PVP electrospun nanofibers due to the efficient energy transfer from Ce3+ to Tb3+ ions is observed. The PL intensity of the electrospun nanofibers decreases gradually with the addition of Ag nanoparticles. No obvious surface plasmon resonance enhanced luminescence is observed. The reasons for the weakening of the emission intensity with the addition of Ag nanoparticles have also been discussed in this work.

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Up-conversion luminescence characteristics under 975 nm excitation have been investigated with Tb3+/Tm3+/Yb3+ triply doped tellurite glasses. Here, green (547 nm: D-5(4) --> F-7(4)) and red (660 nm: D-5(4) --> F-7(2)) up-conversion (UC) luminescence originating from Tb3+ is observed strongly, because of the quadratic dependences of emission intensities on the excitation power. Especially, the UC luminescence was intensified violently with the energy transfer from the Tm3+ ions involves in the Tb3+ excitation. To the Tb3+/Tm3+/Yb3+ triply doped glass system, a novel up-conversion mechanism is proposed as follows: the energy of (3)G(4) level (Tm3+) was transferred to D-5(4) (Tb3+) and the 477-nm UC luminescence of Tm3+ was nearly quenched. (C) 2006 Elsevier B.V. All rights reserved.

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Phosphate glasses 60P<inf>2</inf>O<inf>5</inf>-15CS<inf>2</inf>O- 15Al<inf>2</inf>O<inf>3</inf>-10BaO were made by high temperature melt-annealing method. The absorption spectra, excitation spectra and emission spectra of Gd<sup>3+</sup>-Tb<sup>3+</sup> and Ce<inf>3+</inf>-Gd<sup>3+</sup>-Tb<sup>3+</sup> co-doped phosphate glass 60P<inf>2</inf>O<inf>5</inf>-15CS<inf>2</inf>O- 15Al<inf>2</inf>O<inf>3</inf>-10BaO were studied. The experimental results indicate that, the doping of Ce<inf>3+</inf> and Gd<sup>3+</sup> in Tb<sup>3+</sup> phosphate glass has a good effect on the 545 nm emission of Tb<sup>3+</sup> at UV excitation. The Ce<inf>3+</inf>-Gd<sup>3+</sup>-Tb<sup>3+</sup> co-doped phosphate glass have a good x-ray luminescence at the radiation of x-ray with energy in 50-120 kev, and a high space resolution. The Ce<inf>3+</inf>-Gd<sup>3+</sup>-Tb<sup>3+</sup> co-doped phosphate luminescence glass is a promising material for using in the digital radiography system in medical devices.