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INOR 368
Synthesis of colloidal II-VI and IV-VI metal sulfide semiconductor nanowires by the solution-liquid-solid growth mechanism
Jianwei Sun and William E. Buhro, Department of Chemistry, Washington University, 1 Brookings Dr, Campus Box 1134, Saint Louis, MO 63130, jsuna@artsci.wustl.edu
High-quality monodisperse crystalline semiconductor nanowires (NWs) are of both scientific and technological interest due to their wide range of optical and electrical properties. Here we demonstrate the synthesis of colloidal II-VI and IV-VI metal sulfide semiconductor NWs via the solution-liquid-solid (SLS) growth mechanism developed by our group. The NWs are grown by using single-source metal diethyldithiocarbamate precursors and Bi nanoparticles serving as the catalyst in trioctylphosphine oxide (TOPO) solvent. The structure of the NWs is determined by XRD and TEM studies. The absorption and the photoluminescence properties are also studied, which demonstrate quantum-confinement effects.
INOR 369
Synthesis of silicon carbide nanotubes by chemical vapor deposition
Nongyue He, State Key Laboratory of Bioelectronics, Southeast University, 210096 Nanjing, China, Fax: 86-25-83790885, nyhe1958@163.com, Deliang Tao, Hunan Key Laboratory of Green-Packaging and Application of Biological Nanotechnology, Hunan University of Technology, Zhengfang Xie, State Key Lab of Advanced Ceramic Fibers & Composites, National University of Defense Technology, and Song Li, Hunan Key Laboratory of Green Packaging and Application of Biological Nanotechnology, Zhuzhou Institute of Technology, Wenhua Lu, Zhuzhou 412008, China, Fax: 86-733-2182097, solisong@163.com
Silicon carbide (SiC), a typical non-oxide ceramic compound with excellent oxidization resistance, outstanding corrosion resistance, high thermal conductivity with low thermal expansion coefficient, high hardness and abrasion resistance, has been paid great attention. Silicon carbide nanotubes (SiCNTs) were directly synthesized here by chemical vapor deposition (CVD). Methyltrichlorosilane was selected as SiC gaseous source, ferrocence and thiophene as the catalyst and the cocatalyst, respectively. The influences of reaction temperature, contents of catalyst and cocatalyst, and content of gaseous source on morphologies of the products were investigated, respectively. The products were identified by high-resolution transmission electron microscopy, scanning electron microscopy, x-ray diffraction and energy-dispersive x-ray, respectively. The synthesis of SiCNTs by CVD is a condition-dependent process. SiCNTs with 20~80 nm in outer diameter and 15~35 nm in inner diameter were observed. The wall structure similar to that of carbon nanotubes was not found for the SiCNTs.
INOR 370
Nanoparticle size and self-assembly within nanoclay hybrid films
Michael Nolan Jr. and Michael E. Hagerman, Department of Chemistry, Union College, Schenectady, NY 12308, nolanm2@union.edu
Comparisons of the inclusion chemistry of Laponite and other synthetic hectorite films offer routes to examine the influence of nanoparticle size and interlamellar cations on organic guest entrapment and host-guest interactions that mediate self-assembly. We have used various cationic rhodamine dyes included within these nanoclay hybrid films as photoprobes of organic-inorganic interfaces and film nanoarchitectures. Detailed optical analyses including electronic absorption and fluorescence spectroscopy have afforded study of how the fluorescence properties of rhodamine changes with respect to concentration and nanoscaffold binding location. Spectral red shifts in both absorption and emission indicated that the chromophores formed J-aggregated dimers with maximum luminescence at very low guest concentrations. H-aggregation and higher order aggregates with reduced luminescence were observed at higher guest loadings. These studies offer synthetic routes for selective tuning of organic-silica interfaces with important implications for future work on optoelectronic devices and gas sensors.
INOR 371
Naturally occurring fluorescent (NOF) mineral inspired luminescent colloidal nanocrystals
Timothy N. Lambert1, Bernadette A. Hernandez-Sanchez1, Timothy J. Boyle1, Harry D. Pratt III1, Nicholas L. Andrews2, Diane S. Lidke2, Janet M. Oliver2, and Bridget S Wilson2. (1) Advanced Materials Laboratory, Sandia National Laboratories, 1001 University Blvd SE, Albuquerque, NM 87106, Fax: (505)-272-7304, tnlambe@sandia.gov, (2) Department of Pathology, The University of New Mexico Health Sciences Center
In an effort to develop new non-cytotoxic luminescent colloidal nanocrystals (NCs) for live cell imaging, we have initiated a NIH-funded program to prepare and evaluate new nanoprobes based on naturally occurring fluorescent (NOF) minerals and lanthanide-doped ceramic oxides. The major goals are to develop new probes that are highly fluorescent, bio-compatible, non-toxic, and tunable. With this in mind we have prepared sphalerite [(Fe/Zn)S], scheelite [Ca(WO4)], manganoan [(Mn/Ca)CO3] and perovskite (CaTiO3) inspired nanomaterials and lanthanide (Dy, Nd, Eu, Tb, Er) doped ceramic oxides, utilizing solution precipitation and solvothermal methods. Surface capping with functionalized poly(ethyleneglycol) molecules/lipids has yielded water soluble NCs that are currently being evaluated for their luminescent properties, as well as their non-toxicity and ability to report on cell-signaling events with various cell lines. The synthesis, materials characterization, water-solubilization methods, biocompatibility and cell-signaling efforts to date will be presented.
This work supported by the Department of Energy, Office of Basic Energy Sciences and the United States Department of Energy under contract number DE-AC04-94AL85000. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the United States Department of Energy.
INOR 372
Synthesis and characterization of mono and multi-element (Nb,Ru)-MSU molecular sieves
Izabela Nowak1, Agnieszka Feliczak1, and Mietek Jaroniec2. (1) Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland,
Fax: +48-61-8658008, nowakiza@amu.edu.pl, (2) Department of Chemistry, Kent State University
Mesoporous (Nb,Ru)MSU-X materials have been successfully prepared for the first time by using tetraethyl orthosilicate, ammonium trisoxalate complex of niobium(V), chloropentaamineruthenium(III) chloride and fatty alcohol polyoxyethylenepolyoxypropylene ether as the sources of silicone, niobium and mesostructure-directing agent, respectively, at different pH values of the synthesis gel. The use of p-octyl phenyl derivatives having different number of PO groups, i.e., 7 or 14, led to the formation of samples of different pore sizes. All the (Ru,Nb)-MSU samples showed diffraction patterns typical for mesostructured materials with a worm-like ordering. The resulting materials featured high surface area (500-1000 sq. m/g), large porosity (mesopore volume up to 0.8 cu. cm/g) and uniform pore size (pore width range: 2.5–6 nm). It appears that ruthenium and niobium were incorporated into the pore walls of these materials.
INOR 373
Effect of synthesis method on the physical and catalytic property of nanosized NiO
Feng Yang, Ying Wu, Tinghua Wu, and Huilin Wan, Institute of Physical Chemistry, Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Zhejiang Normal University, Jinhua 321004, China, ying-wu@zjnu.cn, ying-wu@zjnu.cn
In recent years there has been an increasing interest in the synthesis of nanosized crystalline metal oxides. The physicochemical property of nanoparticles has intimate connection with the preparation technique. Nanosized NiO material was prepared by different methods. It's obvious that synthesis techniques influence the size, shapes and distribution of NiO nanoparticls. Therein NiO prepared by sol-gel and reverse micro-emulsion method has the larger special surface area and better particle distribution, compared with solid-state milling and precipitation method. The special surface area of NiO nanoparticles influences the adsorptive property, which has intimate connection with their catalytic behavior. The undecomposed surfactant covering the partial surface of NiO prepared by micro-emulsion method and calcinated at low temperature restrained its adsorption. Thus, NiO nanoparticles prepared by sol-gel method have good adsorptive property and best catalytic behavior for oxidation dehydrogenation of ethane reaction at lower reaction temperature.
INOR 374
Effects of solvent on properties of TiO2 porous films prepared by a sol-gel method from the system containing PEG
Jinfei Luo and Xiaoxin Liu, School of Chemical Engineering & Technology, Tianjin University, Weijin road 92, Tianjin 300072, China, Fax: 86-22-87401961, luojinfei@tju.edu.cn
Four different solvents were used to prepare porous TiO2 films by the sol-gel method from the system containing tetrabutylorthotitanate as starting material and PEG as a template. The comparison of effects of the four solvents on the porous structure, film thickness, crystallization behavior from amorphous to anatase and optical properties of the resultant TiO2 porous films are discussed. The maximum thickness of the film prepared by one-run dip-coating reaches over 1.17 ìm when 1-decanol is used as the solvent. The mechanism for formation of the porous structure is interpreted based on the phase separation and self-assembly of PEG in the sol systems. |
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