Fluorescent Sulfide Semiconductor Nanocrystals And Rare Earth Based Luminescence Nanoparticles: Synthesis, Characterization And Applications

Fluorescent semiconductor nanocrystals and rare earth based fluorescence nanoparticles are two major types of luminescence nanomaterials due to the quantum size confinement effect and aboundant configurations of 4f electronic structures, respectively. Fluorescent semiconductor nanocrystals shows fantastic optical properties varied from size dependent luminescence, lower optical bleaching, high quantum efficiency, broad absorption bands, to narrow emission bands. Rare earth based fluorescence nanoparticles possess remarkable optical properties such as high quantum efficiency, low concentration quenching and large stocks'shift. Based above-mentioned properties, fluorescent semiconductor nanocrystals and rare earth based fluorescence nanoparticles have become an important candidate in a varied research areas from biological imaging, medical diagnosis, optoelectronic devices to solar cell.This thesis firstly focus on the synthesization and characterization of sulfide semiconductor nanoparticles in dimethyl sulfoxide(DMSO). In this study, we found the DMSO worked as both solvent and sulfur source,when the metal salts (Zn(NO3)2, Cd(NO3)2, Mn (NO3)2) were dissolved into DMSO and be heated upto high temperature(>130℃), the cation of these salts will react with the sulfur released from DMSO and produce the resulting metal sulfides (ZnS, CdS, ZnS:Mn) nanoparticles.We also characterized the morphology and optical properties of these as prepared semiconductor nanoparticles.The synthesis process and results shows that the experimental procedure is relatively simple and more suitable for commercial production of semiconductor nanoparticles, and its excellent fluorescence properties of these as semiconductor nanoparticles in favor of biological applications such as cell labeling, disease diognosis, biological detection and etc.In this paper, the third chapter, our research move on to the water soluble CuS nanoparticles, we mainly focus on the synthesis and thermal ablation effect on the treatment of cancer cell. Firstly, we synthesized the CuS nanoparticles with appropriate ligands wich providing hydrophilic ends means water solubility in water, and investigated the crystal phase, morphology, optical, photothermal properties of these as prepared CuS nanoparticles. Good performance of the infrared light based photothermal effect prompted us to apply it to women cervical cancer cells (Hela cell) in vitro photothermal ablation treatment upon a infrared light with a wavelength of 808 nm. The assessment of cytotoxicity and thermal ablation effect of these CuS nanoparticles shows that CuS nanoparticles is very promising to enhance the treatment effect of cancer in photothermal albation therapy due to their excellent thermal properties and lower toxicity. In the fourth chapter, we focus on the research of water soluble cerium oxide (CeO2) nanoparticles. We prepared water soluble CeO2 nanoparticles by a simple wet chemistry method firstly, and later move on to the study of gene toxicity effect of CeO2 nanoparticles on human epithelial cells. The sister chromatid exchange and single cell gel eletrophoresis investigation reveals that the gene toxicity of CeO2 nanoparticles is low and it's proper to apply the CeO2 nanoparticles in ophthalmic research.In the fifth chapter, we mainly paid our efforts to synthesis and characterization of CePO4:Tb/LaPO4 core-sheathe fluorescent nanowires. We first synthesized monodisperse CePO4:Tb nanoparticles, and second, allied them in one direction, finally coating the outside of the aggregation with LaPO4 by follow-up reaction, resulting the CePO4:Tb/LaPO4 fluorescent nanowires.The morphology investigation and fluorescence enhancement proved the successful coating of LaPO4 layer. The successful synthesization of CePO4:Tb/LaPO4 shows that the rare earth phosphate nanowires can also be obtained under ambient environment, and this simple synthesization method and opticals properties in favor of rare earth phosphate nanowires in comercial production and fabrication of solid state lighting and optoelectronic devices.