Template Preparation Of Rare Earth Polymer Micro/nano Materials And Its Performance Research

The template method is an effective method for the preparation of hollow rare earthluminescent materials due to its direct, simple and efficient advantages. It will have broadapplication prospects in chemical preparation and synthesis of new functionalmaterials.This dissertation focuses on the preparation of hollow rare earth luminescentmicrospheres via a hydrothermal route using polymer （PS or MF） as a template. Themorphology-controlled synthesis and fluorescence properties of the products were studiedwidely and the anticipated experimental results have been obtained. The main content is asfollows.Y₂O₃:Tb³⁺hollow microspheres have been successfully prepared on a large scale withpolystyrene microspheres as templates followed by subsequent calcination. All X-raydiffraction peaks can be indexed to the pure cubic phase of Y₂O₃. Transmission electronmicroscopy and scanning electron microscopy images indicate that the average size of thehollow spheres is ca.1.3μm and the thickness of the shells is ca.50nm. The microspheresshow a strong green emission corresponding under ultraviolet excitation.The optimum Tb³⁺concentration was3mol%to obtain the highest photoluminescence intensity. This studyindicates that a calcining temperature of800℃is needed for high luminescence efficiency.YPO₄:Eu³⁺hollow microspheres were synthesised by using the spheres ofPS/Y（OH）CO₃:Eu³⁺as a precursor. The whole process mainly consists of the hydrothermalreaction and calcination. The YPO₄:Eu³⁺hollow spheres were characterised by X-raydiffraction, scanning electron microscopy, transmission electron microscopy andphotoluminescence. The formation mechanism was also investigated. The obtainedYPO₄:Eu³⁺hollow spheres may have potential applications in cell biology, drug releaseand diagnosis, because of high chemical stability and luminescence functionality.YVO₄:Eu³⁺hollow microspheres have been successfully fabricated via a urea-basedhomogeneous precipitation method in the presence of colloidal melamine formaldehyde resin （MF） microspheres as templates,without heat treatment. X-ray diffraction （XRD）,scanning electron microscopy（SEM）, transmission electron microscopy（TEM）,photoluminescence（PL） spectra, and the kinetic decay were employed to examine theresulting phase formation, morphology and luminescent properties. The XRD result revealsthat the doped sample is of high crystallization which is assigned to the pure tetragonalphase of YVO₄. Upon excitation by ultraviolet excitation, the YVO₄:Eu³⁺sample showsstrong red light emission.