Synthesis And Luminescent Properties Of Rare Earth Fluoride Nano-phosphors

Nanometer material was developed in late 80's,and early 90's as a new subject,which development has brought a significant change to the industry in twenty-first century.Due to some advantages,such as the quantum size effect,small size effect between the nanoparticles,surface effect,and the macroscopic quantum tunnel effect,the study on preparation and properties of nano materials become the research hotspot at present,and has aroused wide attention of scientists.Due to energy levels and special 4f-electronic-shell structure of rare-earth element,the materials doping rare earth become ideal photoelectric functional material.As the light matrix materials,fluoride doping rare earth have excellent optical characteristics,such as,low phonon energy,high chemical stability,excellent optical transparency,wide light transmission range,which decrease nonradiative relaxation phenomenon,effectively improve the advantages of optical life and light efficiency of rare earth ion.The fluoride doping rare earth have important application prospect in high-definition display,solid state laser,infrared detection,biological analysis and medical diagnosis and other fields.In this paper,the main research contents are as follows:?1?The amino modified?-NaY?Gd?F₄:Yb³⁺/Er³⁺nanorods were synthesized by hydrothermal process using polyethyleneimine?PEI?as a surfactant.The preparation conditions of?-NaY?Gd?F₄:Yb³⁺/Er³⁺nanorods were also studied.The results indicated that pure?-NaY?Gd?F₄:Yb³⁺/Er³⁺can be obtained under 40mol%Gd³⁺ions induced at 200?for8h.The crystal structure,morphology and luminescent properties of final products were characterized by X-ray diffraction?XRD?,field emission scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and fluorescence spectra?PL?,respectively.The XRD and SEM?TEM?revealed that the as-synthesized samples presented a pure phase?-NaY?Gd?F₄:Yb³⁺/Er³⁺nanorods with average diameter of 40 nm and average length of 210nm.Under 980 nm excitation,four emissions peaks centered at 407 nm,529 nm,546 nm and660 nm were observed,and these emissions were corresponding to the ²H_9/2?⁴I_15/2,²H_11/2?⁴I_15/2,⁴S_3/2?⁴I_15/2,and ⁴F_9/2?⁴I_15/2 transitions of Er³⁺,respectively.The amino groups on the surface of the?-NaY?Gd?F₄:Yb³⁺/Er³⁺nanorods can be coupled with bovine serum albumin?BSA?via a glutaraldehyde method.The conjugation of between?-NaY?Gd?F₄:Yb³⁺/Er³⁺nanorods and BSA can be confirmed by UV spectroscopy and Coomassie-brilliant-blue method at room temperature.?2?By adjusting the molar ratio of oleic acid?OA?,oleylamine?OM?,and 1-octadecene?OD?ligands in reaction solution,Eu²⁺-doped BaSiF₆ nanophosphors were synthesized via a thermal decomposition synthesis route.Eu²⁺ions have been successfully doped into BaSiF₆host lattice and strong 4f⁷(⁶P_5/2)?4f⁷(⁸S_7/2)line emission of the Eu²⁺in BaSiF₆ matrix is observed at room temperature.Meanwhile,the dependence of photoluminescent?PL?intensity of BaSiF₆:Eu²⁺nanophosphors on doping concentrations were also studied.?3?Eu²⁺-doped BaSiF₆ nanorods with average diameter of 200 nm and average length of1⁴?m were synthesized via a hydrothermal method.Under 257 nm excitation,the f-f transitions of Eu²⁺,located at 359nm[4f⁷(⁶P_5/2)?4f⁷(⁸S_7/2)]can also be observed in the products at room temperature.Meanwhile,the crystal structure and morphology of final products were characterized by X-ray diffraction?XRD?,field emission scanning electron microscopy?FE-SEM?.