Facile Synthesis And Fluorescent Properties Of Water Soluble Lanthanide-Doped Fluoride Nanomaterials

Chitosan/LaF₃:Eu³⁺ nanocomposite particles were prepared by a very simple coprecipita- tion method in absolute aqueous. The samples were characterized by transmission electron microscopy ( TEM ), X-ray diffraction ( XRD ) and Fourier transform infrared ( FT-IR ) fluorescence spectra. The results showed that the nanocomposite particles had an average size of about 20 nm. And the chitosan covered on the particles rendered them water-soluble as well as afforded amino and hydroxyl groups on their surface. Further, this paper exhibited the excitation and emission spectra of these nanocomposite particles and described the luminescent mechanism corresponding the level. The results showed that the samples reached the maximum fluorescence intensity when Eu³⁺ doped molar concentration of 10 % in the LaF₃ crystals. Finally, the successful coupling of the finished chitosan/LaF₃:Eu³⁺ nanocomposite particles and the fluorescent protein ( FITC ) shows their potential values in the biology areas. Core- shell structure LaF₃:Eu³⁺/SiO₂ nanoparticles were synthesized. Fourier transform infrared ( FT-IR ) measurement was performed to demonstrate the existence of SiO₂ on the nano- crystals and hydrophilic of LaF₃:Eu³⁺/SiO₂ nanoparticles. The nanocomposite particles are very suitable for use in biological applications, for example, intracellular labelling or measurements, because they are very small in size. The use of this method can be extended to the synthesis of other water soluble and biocompatible lanthanide( III )-doped luminescent nanocrystals( such as LaF₃:Nd³⁺; LaF₃:Yb³⁺,Er³⁺ nanocry- stals and so on ).