Synthesis And Properties Of Rare Earth Luminescense Micro/Nano Materials Through Template Assisted Methods

In recent years,Rare earth?RE?based materials exhibit good luminescent properties,chemical/photochemical inertness,and low toxicity,aroused much attention because they have been extensively used as the most promising functional material in various fields.This dissertation focuses on the preparation of rare earth luminescent microsphere via sacrifice template and polymer template.The morphology controlled synthesis,fluorescent properties have been researched systematic systematically and the anticpated experimental results have ben obtained.The main content is an follows:Subglobose YBO₃:Ln³⁺?Eu,Tb?phosphors have been successfully synthesized via a simple solutionbased hydrothermal method using Y2?CO3?3?H2O?2 colloid spheres as the precursor.The crystal structure,morphology,chemical composition and photoluminescence property of the phosphors were investigated by XRD,TEM,PL.The as-prepared phosphors present subglobose morphology and have a diameter of about 1?m.The YBO₃:Eu³⁺ exhibited strong orange emission with good R/O ratio indicates a better color purity than bulk counterparts.The YBO₃:Eu³⁺ exhibited strong green luminescence feature.The YPO₄:Eu³⁺ hollow microspheres have been successfully prepared via a simple two-step route.First,the core-shell structured MF@Y?OH?CO3:Eu precursor was fabricated by a urea-based homogeneous precipitation method using weak cross-linking colloidal melamine formaldehyde?MF?microspheres as template.Then the Y?OH?CO3:Eu precursor was transformed into hollow YPO₄:Eu³⁺ by a subsequent solvothermal method,and MF microspheres were dissolved in the solvent simultaneously.From SEM and TEM,the uniform microspheres with narrow size distribution hollow spheres were observed.Theobtained YPO₄:Eu³⁺hollow spheres with the high luminescence,high color purity,good color rendering and functionality chemical stability.SiO₂@Y₂O₃:Eu³⁺ hollow mesoporous microspheres were prepared by coating luminescent Y₂O₃:Eu³⁺ particles onto uniform silica spheres using positive charged melamine formaldehyde microspheres as sacrificial templates.Various approaches including X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared,thermogravimetric and differential thermal analysis,photoluminescence spectroscopy and N2 adsorption/desorption were used to characterize the samples.The results indicate that SiO₂@Y₂O₃:Eu³⁺ particles form the prediction morphology with hollow silica spheres shell,and the composite microspheres exhibit mesoporous characteristics and the total pore volume are 202.8 m2/g.In addition,drug release tests suggest that the composite has a controlled drug release property with ibuprofen as the model drug.