Preparation And Luminescent Design Of One Dimensional Rare Earth Luminescent Materials

Rare earth upconversion micro/nano luminescent material is a kind of star material which absorbs low photon energy and converts it into high photon energy.Because of its unique luminescence characteristics,such as no background luminescence,high spectral purity and no bleaching,the material has been widely used in new light sources,display imaging,anti-counterfeiting,luminescent probes and imaging fields.Luminescence is the most advantageous function of rare earth compounds in the three major functions of light,electricity and magnetism.Therefore,the exploration and research of rare earth luminescent materials has a very important strategic significance.However,due to the parity forbidden transition of the light source in 4f electron layer,together with the surface effect,the low luminescence efficiency and the low spatial resolution of single particle luminescence pattern restrict its practical application.In order to enhance the luminescence efficiency and visualize the single particle luminescence pattern,the luminescence emission enhancement,transport and pattern regulation of one-dimensional single particle NaYF₄:Yb³⁺/Ln³⁺(Ln³⁺=Er³⁺,Ho³⁺and Tm³⁺)micro/nanorods were studied by confocal microscopy imaging mode system.The physical mechanism of controlling luminescence intensity and pattern regulation was revealed.The research is divided into the four parts:The first part reviewed the research status of rare earth upconversion luminescent materials.the research background of 4f in layer spectral theory of rare earth ions and Yb³⁺sensitized doped luminescent materials system is introduced.the progress and problems of synthesis and spectral regulation of rare earth luminescent micro/nano materials in recent years are summarized and reviewed,and the research purpose and content of this subject are proposed.In the second part,a series of NaYF₄:Yb³⁺/Ln³⁺(Ln³⁺=Er³⁺,Ho³⁺and Tm³⁺)micro/nano crystals were synthesized by hydrothermal method.The luminescence and spatial pattern characteristics of single NaYF₄:Yb³⁺/Ln³⁺(Ln³⁺=Er³⁺,Ho³⁺and Tm³⁺)were studied by laser spectroscopy.The integral intensity of the upconversion luminescence of a single microtube in the waveguide excitation mode is 10 times higher than that in the point excitation mode.The attractive spatial luminescent patterns,including a dual-colour dumbbell,sunflowers,rod-shaped candy,dichroic plates,and coloured rings,are obtained.Based on the physical effects of waveguide,diffraction and interference,the physical mechanism behind the formation of these unique patterns is explained,suggesting that the The application potential of conversion materials in anti-counterfeiting and display fields.In the third part,one-dimensional NaYF₄:Yb³⁺/Er³⁺micro/nano crystals?rods and tubes?with controllable aspect ratio were synthesized by sodium citrate assisted hydrothermal method.The generation,transport and target output of upconversion luminescence in one-dimensional rod are studied by using laser spectrum confocal microscope system.The spatial distribution pattern of luminescence is studied by changing excitation mode and constructing core-shell structure samples,and the mechanism of luminescence transport and target output is revealed.These luminescent waveguides have potential applications in photon coupling devices,upconversion waveguides,luminescence imaging and photodynamic therapy.The fourth part summarizes the research content of this paper,and looks forward to the possible research of single particle in the future.