Abstract
We designed highly aqueous dispersible CeF3:Tb@LaF3@SiO2 nanoparticles. The epitaxial growth of inert LaF3 shell and further amorphous silica, respectively, enhanced their optical and luminescence properties, which is highly usable for luminescent biolabeling, and optical bio-probe etc.
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Highly luminescent and aqueous soluble CeF3:Tb (core),CeF3:Tb@LaF3(core/shell) and CeF3:Tb@LaF3@ SiO2 (core/shell/Si) nanoparticles(NPs) with mean particle size 12nm were prepared by co-precipitation method at low temperature. X-ray diffraction pattern verified the phase purity, high crystallinity of hexagonal structure. The TEM image and SAED pattern revealed the single phase polycrystalline nature, well-dispersed irregular shaped hexagonal structure. FTIR spectra show the characteristic infrared peaks of silica, it suggests the successful silica surface coating around the core/shell NPs. The excitation and emission intensity of core/shell NPs were remarkably increased then their counterpart core NPs. It implies that a significant amount of nonradiative transition centers existing on the surface of core NPs has been eliminated due to the formation of passivated LaF3 layer. The silica surface modification over the core/shell NPs strikingly enhanced the solubility character in an aqueous environment.