Preparation And Properties Of Rare Earth Ions-doped Oxide Luminescence Nanomaterials

Rare earth luminescence materials are widely used in the fields of flat panel display, green lighting, optical communications and laser devices. Rare earth oxides are excellent matrixes for luminescent materials. Rare earth doped luminescent nanomaterials coated with a layer of undoped matrix materials can reduce surface defects of nanomaterials, which would improve the photoluminescence properties. In this dissertation, rare earth oxides luminescence nanomaterials with different morphologies were synthesized with homogeneous precipitation, hydrothermal and sol-gel method. Some meaningful results were obtained. The results were summarized as follows:1. Uniform spherical Gd2O3:Eu3+ luminescence nanomaterials with different Eu3+ doping concentration and Gd2O3:Eu3+@Y2O3 core-shell structural composite particles with different shell thickness were prepared by homogeneous precipitation method. Photoluminescence properties of Gd2O3:Eu3+ nanoparticles coating with different thickness of Y2O3 host on the surface were mainly studied. It is found that when the coating thickness is suitable, that is Gd2O3:Eu3+/Y2O3 ratio of R=4:1, the luminescence intensities of core-shell particles are higher than that of the Gd2O3:Eu3+ core nanocrystals, it is thought that the core-shell samples decrease the negative effects of nanoparticles on the luminescence properties.2. Uniform spherical Y2O3:Eu3+ luminescence nanomaterials and Y2O3:Eu3+@Gd2O3 core-shell structural composite particles with different Eu3+ doping concentration were prepared by homogeneous precipitation method. Photoluminescence properties show that the luminescence intensities of core-shell composite particles are higher than that of the Y2O3:Eu3+ core nanocrystals. It is thought that the intensity difference between core-shell structure and un-coated nanoparticles was related to the quenching concentration of Eu3+3. Spherical YVO4:Eu3+ luminescence nanoparticles and YVO4:Eu3+@GdVO4 core-shell structural composite particles were synthesized by hydrothermal method. Photoluminescence spectra show that the luminescence intensities of YVO4:Eu3+@GdVO4 core-shell composite particles are higher than that of the YVO4:Eu3+ core particles.4. (1) GdVO4:Eu3+ and GdVO4:Eu3+@GdVO4 luminescence materials with smooth surface were prepared by sol-gel method. The diameter of un-coated sample is 310 nm, and the thickness of coating layer is about 45 nm.(2) Sandwich structure GdVO4:Eu3+ and GdVO4:Eu3+@YVO4 core-shell structural particles were prepared by hydrothermal method. The diameter of un-coated samples is 335 nm and the thickness is 110 nm. The thickness of coating layer is about 10 nm.Photoluminescence spectra show that the luminescence intensities of core-shell GdVO4:Eu3+@LnVO4 (Ln=Gd, Y) composite particles are higher than that of GdVO4:Eu3+ core particles fabricated by the above two methods.