Studies On Optical Properties And Hydrothermal Synthesis Of Binary Rare-Earth Fluorides

Because of the high productions,high stability and excitation wavelength tunable, Rare-earth fluoride micro-nanocrystals have received extensive attention due to their potential applications in optics, optoelectronics, biological labeling, catalysis fields, etc.Meantimes, it still remains a great challenge to Precisely control the size, morphology, and crystal structure of rare-earth fluorides for tailoring their relative properties, especially photoluminescence.Besides, crystal structure is one of the most important factors that can influence the photoluminescence of rare-earth fluoride micro-nanocrystals, so we are concerned about the direct correlation between the crystal structure of the rare-earth fluorides and their morphologies.In the thesis we use a simple hydrothermal method, by adding complexing reagents EDTA, in order to control the speed of the reaction release of reagents, reducing the growth rate of crystals, and ultimately to achieve to the purpose of controlling crystal morphology of synthetic binary rare-earth fluoride micro-nanocrystals. Study the formation mechanism of binary rare-earth fluorides, and explore the optimum reaction conditions of rare-earth fluoride by hydrothermal synthesis and using XRD, SEM characterize the structure and morphology of samples, and study the different lanthanide fluoride crystal growth habit and different structure of lanthanide fluoride have affect on the morphology of the final product.Meantimes, optical oroperties of the rare-earth fluorides are firstly studied.The main results achieved in this paper are listed as following:(1) Synthesis and characterization of Binary Rare-earth Fluorides.A series of LnF3 (DyF3,ErF3,NdF3,SmF3) nano-materials are prepared by a simple hydrothermal method. The structure and morphology of asprepared products are characterized by X-ray power diffraction (XRD), field emission scanning electron microscopy (FE-SEM). Through a series of experiments, we found that reaction conditions have a great impact on the morphology and size of the inorganic nano-materials. Meantimes, the formation mechanism and fabrication of SmF3 hexagonal phase globular nanocrystals are intensively studied.(2) Synthesis and characterization of Nd3+,Eu3+-doped YF3 micro/nano. Ln3+:YF3 frustum-octahedron micro/nano have been prepared by a simple hydrothermal method. The structure and morphology of asprepared products are characterized by X-ray power diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM),etc.The results show that the morphology of asprepared products are not changed obviously.The same morphology of Ln3+-doped YF3 frustum-octahedron micro/nano can be successfully prepared by hydrothermal method.Meanwhile, the formation mechanisms of Ln3+:YF3 frustum-octahedron micro/nano are studied simply.At last,The optical properties are studied initially.(3) Synthesis and Fluorescence Analysis of Er3+and Yb3+codoped YF3 micro/nano.The efficient green and red up-conversion (UC) luminescence of Er3+ and Yb3+ codoped YF3 is detected under a 980-nm IR excitation. There are three emission bands located at 517-525,535-545, and 657 nm corresponding to an electron transfer from the excited states 2H(11/2),4S(3/2), and 4F(9/2) to the ground state 4I(15/2), respectively. NAME:liyanbing Supervised by Sunyufeng...