Controlled Synthesis,photoelectric And Optical Properties Of The Core Shell Nanostructure

In recent years, lanthanides ions doped nanoluminescence materials have a wide range of applications in various fields because they have many advantageous features such as high absorptive capacity, stable physical and chemical properties and good luminescence properties. However, lanthanides ions doped nanoluminescence materials not only are easily oxidized at high temperature but also have low upconversion efficiency,so their applications in some fields are limited. Therefore this paper takes the lanthanides ions doped fluoride materials as research object, through coated oxide on fluoride surface to prevent it from being oxidized and coated fluoride to improve the luminescence efficiency.The NaYbF4:Tm3+ nanoparticles were prepared by a solvothermal process and the NaYbF4:Tm3+@TiO2 core-shell structures via a method similar to the Stober process based on the hydrolysis and condensation of TBOT. The XRD and TEM images showed size and morphology of the core-shell structures. The luminescence spectral of different concentration of Tm3+ ions doped NaYbF4 nanoparticles and NaYbF4:Tm3+@TiO2 core-shell structures were tested. The effect of different concentration of Tm3+ ions and TiO2 shell on the luminescence efficiency of NaYbF4:Tm3+ nanoparticles have been analyzed with the energy diagram.The monodispersed of NaGdF4:20%Yb3+,2%Tm3+ nanoparticles and NaGdF4: 20%Yb3+,2%Tm3+@NaYF4 core-shell structures were synthesized by decomposed the three trifluoroacetic salt. The XRD and TEM images showed size and morphology of the samples. We studied the effect of different concentration of Yb3+ ions and NaYF4 shell on the upconversion luminescence of NaGdF4:Yb3+, 2%Tm3+ nanoparticles, and analyzed the upconversion luminescence mechanism combined with the energy diagram. The results indicated that the upconversion efficiency of the core-shell structures were improved.The monodispersed of NaYF4:20%Yb3+,2%Er3+ nanoparticles and NaYF4: 20%Yb3+, 2%Er3+@NaYF4 core--shell structures were synthesized by decomposed the three trifluoroacetic salt. The NaYF4:20%Yb3+,2%Er3+@NaYF4@SiO2 core – shell structures were prepared via a method similar to the Stober process based on the hydrolysis and condensation of TBOT. The XRD and TEM images showed size and morphology of the samples. We studied the effect of different concentration of Yb3+ ions?NaYF4 shell and SiO2 shell on the upconversion luminescence of NaYF4: Yb3+,2%Er3+ nanoparticles and analyzed the upconversion luminescence mechanism combined with the energy diagram. The results indicated that the NaYF4 shell can improve the upconversion efficiency and the SiO2 shell can prevent it from being oxidized.