Synthesis And Optical Properties Of Noble And Rare Earth Nanoparticles

Metal nanoparticles, nanoplates, nanorods, and nanowires exhibit strong absorption band due to the surface plasmon resonance of the noble nanoparticles. The frequency and intensity of the surface plasmon resonance is influenced by the compositon, shape, size of the noble nanoparticles and the surrounding enviorment. Excitation of the surface plasmon resonance of noble nanoparticles can create strong local optical field. The strong local field may lead to many experiments, such as enhanced optical absorption, surface enhanced Raman scattering, and surface enhanced fluorescence, and so on, which has broad applications in areas such as ultrafast information processes, nonlinear spectra and biological fluorescence labeling.The rare earth has a very wide range of applications in the metallurgical, mechanical and aerospace and many other fields. Due to the rich rare earth resourses, the research on the rare earth materials has important significance for the scientific and technological progress of our country. Rare earth luminescence materials have aroused great concern, due to their sharp fluorescence, long fluorescence lifetime, excellent photostability and low toxicity. Rare earth luminescence materials have great value in many areas such as biological fluorescence labeling.(1) Au nanorods have been successfully synthesized at the temperature of90℃by using the co-surfactant solution of hexadecyltrimethylammonium bromide and benzyldimethylammoniumchloride hydrate. The longitudinal surface plasmon absorption band could vary between680and770nm by adjusting the molar ratio of CTAB BDAC from0.5to2. At90℃, nanorods with a longitudinal surface plasmon absorption peak of770nm can be obtained when the molar ratio of to CTAB BDAC was2:3.(2) Au-Ag nanoshuttles with sharp tips at both ends have been synthesized in glycine solution by chemically depositing silver on gold nanorods. Strong local field in the Au-Ag nanoshuttles enhanced by longitudinal surface plasmon resonance (LSPR) were investigated. At the corresponding LSPR wavelengths, the absorption intensity of the Au-Ag nanoshuttles is about1.5times that of the original Au nanorods.(3) The influence of the core-shell Ag-SiO2nanowires on the fluorescence property of the heptamethine cyanine NIR laser dye is investigated. The photoluminescence intensity and lifetime of the heptamethine cyanine dye are affected by the Ag-SiO2nanowires. When the thickness of the SiO2shell was27nm, the PL of the Ag-SiO2-dye nanowire is27times that of the dye.(4) Au-CdS core-shell hetero-nanorods were synthesized and the optical properties were investigated. Exciton-plasmon interactions in the Au-CdS nanorods induce shell thickness-tailored surface plasmon resonance. Furthermore, these Au-CdS nanorods demonstrate an enhanced two-photon luminescence under near-infrared pulsed laser excitation.(5) The upconversion fluorescence properties of the hexagonal-phase uniform NdF3and NaNdF4NCs were investigated by using picosecond laser at the excitation wavelength of800nm. The NaNdF4NCs exhibited～400times stronger upconversion fluorescence than the NdF3NCs under the same excitation power of240mW. When the excitation power was over the threshold of270mW, all the emissions of the NdF3NCs film at around525,585, and640nm exhibited avalanche increasing with the slope up to～12.0. For the NaNdF4NCs film, one new emission centered at～680nm appeared when the excitation power was increased.