Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials

Hydrthermal Synthesis Alkaline Fluroides Nanomaterlas and Host for Lanthaide Near-Infrared Luminecent Properties

Author HouSuYing
Tutor XingYan
School Northeast Normal University
Course Physical and chemical
Keywords nano/micromaterials hydrothermal synthesis alkaline fluorides Near-Infrared Luminescent Properties
CLC TB383.1
Type Master's thesis
Year 2011
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In recent years, nanomaterials with novel nanostructures and strange characters haveattracted significant attention. Here, we used simple hydrothermal method and designeddifferent solution chemical route, and synthesized BaF2 and CaF2 nanomaterials with differentmorphologies. X-ray diffraction, scanning electron microscopy, electron diffraction,transmission electron microscopy, and photoluminescence spectra were used to characterizethe samples. The formation process of the fluorides nanomaterials has been investigated basedon the experiments in detail. Additionally, the near-infrared luminescence of lanthanide ions(Er, Nd, and Yb) doped fluorides nanomaterials were discussed in detail.1. By a simple hydrothermal approach, hollow BaF2 microspheres have been fabricatedwith the help of the triblock copolymer of EO20PO70EO20 (P123) . The samples werecharacterized by X-ray diffraction, scanning electron microscopy, electron diffraction,transmission electron microscopy, and photoluminescence spectra field emission scanningelectron microscopy, energy-dispersive x-ray spectroscopy. Contrast experiments indicatedthat the complexant of citrate played important roles for the formation of hollow BaF2 spheres.Furthermore, the use of NaBF4 is indispensable for obtaining the microstructures. A softtemplating mechanism has been discussed.2. Highly uniform three-dimensional flowerlike CaF2 nanostructures have beensuccessfully prepared by a facile hydrothermal method assisted by a chelating reagent,ethylenediamine tetraacetic acid disodium salt (Na2EDTA). The nanoflowers are assembledby numerous nanosheets with a thickness of 10 nm. The formation process of the hierarchicalCaF2 nanoflowers has been investigated in detail. It is found that reaction time and chelatingreagent play a key role in forming the hierarchical nanoflowers. Furthermore, thenear-infrared luminescence of lanthanide ions (Er, Nd, and Yb) doped CaF2 nanostructures,especially in the 1300-1600 nm region, was discussed and of particular interest fortelecommunications applications.3. Highly uniform and well-dispersed mulberry-like nanostructural of CaF2 weresynthesized by a hydrothermal method without the assistance of any template or surfactant.X-Ray diffraction, scanning electron microscopy and transmission electron microscopy wereused to characterize the samples. In addition, the luminescence of Yb3+-doped CaF2nanostructures were discussed and of particular interest for various photonic applications inionic crystals and glasses.

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