Construction And Characterization Of Divalent Rare Earth Ions-doped Alkaline Earth Metal Fluoride Halides One-dimensional Nanostructures

BaXY?X,Y=F,Cl,Br?are wonderful luminescent host materials,and they can exhibit efficient photostimulated luminescence via doping with Eu²⁺ ions activators.BaXY:Eu²⁺?X,Y=F,Cl,Br?materials have been widely used in optical signal processing,storage system and X-ray radiation image intensifying screen,etc.Presently,BaYX:Eu²⁺?X,Y=F,Cl,Br?materials have been extensively studied and successfully obtained by high-temperature solid state reaction,ball-milling method,hydrothermal and solvothermal method,etc.Different morphological BaYX:Eu²⁺?X,Y=F,Cl,Br?materials have been prepared by the above methods,such as nanoparticles,hexagona-shaped nanoparticles and square-like microplates.However,to our knowledge,no reports on preparation of BaXY:Eu²⁺?X,Y=F,Cl,Br?nanofibers can be found in literatures.Electrospinning is a simple,straightforward and versatile method to fabricate 1D micro-and nanomaterials.Hence,it is an important and meaningful subject of study to fabricate BaXY:Eu²⁺?X,Y=F,Cl,Br?nanofibers by electrospinning technique combined with double-crucible method.In this dissertation,BaXY:Eu²⁺?X,Y=F,Cl,Br?nanofibers were fabricated via electrospinning technique combined with double-crucible method.The samples were characterized by X-ray diffractometry?XRD?,scanning electron microscope?SEM?,transmission electron microscope?TEM?and fluorescence spectroscope.The results show that the BaFX:Eu²⁺?X = Cl,Br?and BaBrCl:Eu²⁺ nanofibers were the tetragonal phase and orthorhombic phase in structure,respectively.The nanofibers have uniform diameter with good dispersity and diameter of nanofibers was 140-210 nm.The luminescence properties of BaXY:Eu²⁺?X,Y=F,Cl,Br?nanofibers were also studied.BaFCl:Eu²⁺ nanofibers exhibit the characteristic blue emission of predominant peak at 387 nm and weak emission at 365 nm respectively originating from 4f65d?⁸S_7/2 and 6P7/2?⁸S_7/2 energy levels transitions of Eu²⁺ under the excitation of 275-nm ultraviolet light.BaFBr:Eu²⁺ and BaBrCl:Eu²⁺ nanofibers exhibit the characteristic purple emission of predominant peak at 390 nm and 402 nm respectively originating from 4f65d?⁸S_7/2 energy levels transitions of Eu²⁺ under the excitation of 280-nm and 287-nm,respectively.These new findings lay the solid foundations for the luminescent properties of BaXY:Eu²⁺?X,Y=F,Cl,Br?low-dimensional nanomaterials.