Hydro-thermal Synthesis And Optical-magnetic Properties Of Several Rare Earth Fluoride Nanocrystals

Lanthanide（Ln） doped rare earth （RE） compounds have excellentphotoluminescence properties, especially fluoride nanocrystals, which have greatpotential applications in solid-laser, color display, biolabels and bioimaging andattracted considerable attention in both fundamental and technological research. Inaddition, compared with organic phosphor and quantum dots, lanthanide dopedupconversion luminescence materials possess advantages such as narrow emissionpeaks, excellent photostability, absence of autofluorescence and low photodamage.Recently, all kinds of fluoride nanocrystal with various shape has been synthesizedalong with the development of solvothermal method. But the nanocrystals used asbioimaging materials especially intracellular bioimaging must present idea crystal,shape, size and upconversion property. Thus, it is very important to synthesize highlyuniform, mondispersed upconversion nanocrystals with controlled crystal phase,shape, and size. In this paper, we synthesized mododisperse ultrsmall Ba₂YbF₇nanocrystals and optical-magnetic coupled multifunctional NaLuF₄microcrystal, ofwhich the structure, shape, and size could be controlled. The main contents of ourworks list below:1、Cubic Ba₂YbF₇monodisperse ultrsmall nanocrystals with average size of about10nm were synthesized with solvothermal method. Experimental results showed thatthe size and optical property of the Ba₂YbF₇nanocrystals can be controlled by themolar ratio of Ba²⁺/Yb³⁺in the precursor solution.2、Heaxgonal NaLuF₄mircotubes were synthesized with solothermal method. Thestructure, shape, and optical property can be controlled by the change of the reactioncondition and doped concentration. The results showd that high NaF concentration inthe precursor solution and high reaction temperature were beneficial the formation ofthe hexagonal phase nanocrystals, which could enhence the optical properties of thenanocrystals. The white emission were achieved by triple doping Yb³⁺/Er³⁺/Tm³⁺andYb³⁺/Ho³⁺/Tm³⁺.3、Monodisperse lanthanide doped NaLuF₄: Ln (Ln=Gd³⁺, Yb³⁺, Tm³⁺) nanorodwere synthesized by a hydrothermal method. The structure, shape, and size of theNaLuF₄nanorod can be controllable by a simple Gd³⁺doping method. The high Gd³⁺doping favored the formation of the hexagonal phase nanorod, and the size of thenanorod gradually decreased as the Gd³⁺doping. The optical and magnetic propertiesof the NaLuF₄nanorod were measured. This optical-magnetic coupledmultifunctional NaLuF₄nanorod may have potential applications in biolables andmagnetic resonance imaging （MRI） as well.