Lanthanide-containing functional materials: Exploratory synthesis and property investigation.

摘要

The research summarized in this dissertation is aimed at the design and exploratory synthesis, characterization, and property investigation of lanthanide-based functional materials. The substances prepared in this work, including small molecular complexes and nanostructured particles, are of fundamental scientific interest as well as practical significance due to the unique chemical and physical properties of the lanthanide elements. Envisioned applications include their uses as light-emitting materials in modern display technology, optical amplifiers, and high-density magnetic recording media. This research seeks to develop general methods for directing the formation of lanthanide materials, particularly as a means of influencing the physical properties of such materials. These efforts are elaborated in distinct yet related projects.; In Chapter 2, exploratory synthesis, structural characterization, and photo-physical investigation of adducts of lanthanide beta-diketonates with a tridentate neutral ligand, TPTZ are described.; In Chapter 3, analogous studies utilizing p,p'-disubstituted bipyridine and phenathroline type bidentate neutral ligands are detailed. The structures of the complexes have been established by single crystal X-ray diffraction. Compositional and structural differences among the various complexes are caused by different structural and electronic properties of the ligands and overall steric compactness of the coordination sphere. Red and green luminescence characteristics of Eu(III) and Tb(III) ions are observed for the corresponding complexes, upon UV excitation, consistent with the well-established ligand-mediated energy transfer and light emission mechanism.; In Chapter 4, the electroluminescence properties of various europium complexes are evaluated for their potential as emissive materials in organic light-emitting diodes.; The synthesis and characterization of Er-doped LaPO4 nanoparticles are described in Chapter 5 together with the preparation and studies of hybrid nanocomposites composed of nanoparticle-doped sol-gels. A single-mode waveguide system was fabricated, wherein Er-doped nanoparticles solubilized in a sol-gel matrix has shown promising performance in propagating light signals (1.54 mum) without significant optical losses.; In Chapter 6, synthesis, electron microscopic characterization and magnetic studies of crystalline Sm(III)- and Eu(III)-doped Fe3O4 nanoparticles are detailed. Magnetic studies suggest the ferromagnetic behavior of the lanthanide-doped Fe3O4 nanoparticles at room temperature and therefore, the significant effects of lanthanide doping.