Controlled Synthesis, Characterization And Optical Properties Of Luminescent Lanthanide Nano-Materials

Due to their unique optical properties, lanthanide nanophosphors haveimportant applications in high-resolution displays, solid lasers and biologicalanalysis. Establishing well-controlled synthetic strategies to these materials,understanding their growth and luminescent mechanisms, and therelationships of their structures, morphologies and optical behaviors, arecrucial to the production of nanophosphors with designated optical properties.This dissertation systematically investigated the controlled synthesis, growthmechanisms and optical properties of lanthanide nanophosphors.Using LnPO₄ family as a model system, the structural and kinetic factorsgoverning the anisotropic growth tendency and shape evolutions on nanoscaleunder hydrothermal environment are systematically studied. AnisotropicLnPO₄ nanostructures are synthesized by a kinetically controlled process,which may serve as a general methodology for generating anisotropicnanostructures. The optical properties of LnPO₄:Eu³⁺ are dependent on theirstructures and morphologies, indicating the possibility of modifying theiroptical properties by structural design.Ln³⁺-doped YF3 nanophosphors have been synthesized by a sonochemicalassisted hydrothermal route. The optical properties of YF₃:Ln³⁺ withpromising applications were studied in depth. In particular, a novel 3-photonmechanism is proposed for a rare blue upconversion (UC) emission inYF₃:Yb³⁺/Er³⁺. Na_0.41Y_0.59F_2.18:Yb³⁺/Er³⁺ UC nanophosphors with controllablesizes have been synthesized by a solvothermal strategy. The study of theirup-conversion luminescence indicated good monochromaticity and UCintensity, which made them promising fluorescent labels for biomolecules.