Rare earth doped fluoride micro-controlled synthesis of nanocrystals of upconversion

Title: Rare earth doped fluoride micro-controlled synthesis of nanocrystals of upconversion luminescence properties of
　　Author: Xue Xiaojie
　　Degree-granting units: Jilin University
　　Keywords: controlled synthesis;; cation effect;; conversion;; fluoride
　　Summary:
　　In recent years, the rare earth fluoride research and development on the conversion quickly. People in the course of the study found that the upconversion luminescence efficiency of material and the material's crystalline structure, size and morphology have a Magnetic lifter great relationship. Therefore, rare-earth ion-doped fluoride conversion materials on the controlled synthesis is to study the relationship between upconversion and size of the key. This paper focus on this issue a more systematic study, and obtained the following results:
　　(1) was successfully prepared by hydrothermal method NaYF_4: Yb ~ (3), Tm ~ (3) micron crystal. Excitation at 980 nm observed a strong blue and ultraviolet upconversion luminescence. By comparing the different samples studied feed concentration, reaction time and F-/Ln ~ (3) molar ratio of the product crystal structure, size and morphology of the specific impact, and analysis of the causes.
　　(2) added to the system NaNO3 studied the reaction of Na ions in the crystal structure changes in the product morphology and size of the impact of http://www.999magnet.com/products/131-magnetic-lifter changes. Through the introduction of the system, such as H ~, Li ~ and K ~ ions, effects of different cations on the product structure.
　　(3) Solvothermal synthesis of NaYF_4: Yb ~ (3), Tm ~ (3) nanocrystals. The nanocrystals can be well dispersed in nonpolar solvents to form transparent colloidal solution. Transparent solution was measured on the conversion spectrum, and analysis of the corresponding upconversion mechanism. Through the hydrolysis of tetrabutyl titanate, diameter about 40 nm were successfully prepared the NaYF_4: Yb ~ (3), Tm ~ (3) / TiO_2 nano core-shell structure and cladding of the TiO_2 impact on the upconversion luminescence.
　　Degree Year: 2010