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Nanoparticles Prepared (nanoparticle + prepare)

Distribution by Scientific Domains
Polymers and Materials Science71%

Selected Abstracts

Nanocrystal Shape Control: Synthesis and Structure,Property Correlation in Shape-Controlled ZnO Nanoparticles Prepared by Chemical Vapor Synthesis and their Application in Dye-Sensitized Solar Cells (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2009
Mater.
Chemical vapor synthesis is a convenient one-step synthesis process for the production of nanocrystalline powders. On page 875, Bacsa et al. report that by controlled variation of experimental parameters, tetrapods (as in image) or spherical ZnO nanocrystals can be selectively obtained directly from Zn metal precursor. Shape control leads to improved optical properties and a better performance when applied as electrodes in dye sensitized solar cells. [source]

Synthesis and Structure,Property Correlation in Shape-Controlled ZnO Nanoparticles Prepared by Chemical Vapor Synthesis and their Application in Dye-Sensitized Solar Cells

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2009
Revathi R. Bacsa
Abstract Here, the large scale synthesis of nanocrystalline ZnO spheres and tetrapods in the size range of 8,40,nm by chemical vapor synthesis using zinc metal as precursor is described. A detailed study of the effect of experimental parameters on the morphology and yield is presented. High-resolution transmission electron microscopy images of the tetrapods show that they are formed by the self assembly of four nanorods in the vapor phase. The tetrapods have optical absorption coefficients that are one order of magnitude greater than the spheres and show intense UV luminescence whereas the spheres show only the green emission. The observed differences in the optical properties are related to the presence of surface defects present in the nanospheres. The tetrapods have increased efficiencies for application in dye sensitized solar cells when compared to spheres. [source]

Composition-Size Effects in Nickel,Zinc Ferrite Nanoparticles Prepared by Aqueous Coprecipitation

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2008
Brian T. Naughton
Nickel,zinc ferrite nanoparticles across the solid solution range, Ni1,xZnxFe2O4, from nickel ferrite to zinc ferrite were prepared by aqueous precipitation of mixed nitrate solutions at the same pH of 12.3. There is a linear relationship between the nanoparticle diameter and composition, decreasing with increasing zinc concentration across the solid solution. The nanoparticles are highly resistant to coarsening and some of them are faceted, suggesting that they are close to thermodynamic equilibrium. Measurements of the surface charge density of the nanoparticles, based on simultaneous conductimetric and potentiometeric titration, are presented as a function of composition for the zinc-rich compositions. A trend exists between the surface charge density and the zinc concentration, suggesting that they may be stabilized by charge. [source]

Microstructure Formation and Property of Chitosan-Poly(acrylic acid) Nanoparticles Prepared by Macromolecular Complex

MACROMOLECULAR BIOSCIENCE, Issue 12 2005
Article first published online: 23 NOV 200
[source]

Microstructure Formation and Property of Chitosan-Poly(acrylic acid) Nanoparticles Prepared by Macromolecular Complex

MACROMOLECULAR BIOSCIENCE, Issue 10 2005
Qi Chen
Abstract Summary: We report here a study on the microstructure formation process of polymeric nanoparticles based on polyelectrolyte complexes. When polyanion poly(acrylic acid) (PAA) was dropped into polycation chitosan (CS) solution, CS-PAA nanoparticles with diverse microstructure would be formed under different experimental conditions. The microstructure of CS-PAA nanoparticles changed from solid spherical nanoparticles to core-shell separative ones and turned back to solid spherical ones with the variation of preparation conditions. The influence of molecular weight of CS and PAA, shell cross-linking, dropping temperature on the size, stability and morphology of CS-PAA nanoparticles were also studied. The nanoparticle size was affected by the molecular weight of CS and PAA, the ratio of amino group to carboxyl group (na/nc) and the incubation temperature as well. The shell-cross-linking provides a means to stabilize these nanoparticles. These nanoparticles can encapsulate plasmid DNA very well, which makes them have great potential in gene delivery. Microstructure of non-cross-linked CS-PAA nanoparticles, encapsulated plasmid DNA, at various na/nc. [source]

Li4Ti5O12 Nanoparticles Prepared with Gel-hydrothermal Process as a High Performance Anode Material for Li-ion Batteries

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2010
Zheng Qiu
Abstract Li4Ti5O12 (LTO) nanoparticles were prepared by gel-hydrothermal process and subsequent calcination treatment. Calcination treatment led to structural water removal, decomposition of organics and primary formation of LTO. The formation temperature of spinel LTO nanoparticles was lower than that of bulk materials counterpart prepared by solid-state reaction or by sol-gel processing. Based on the thermal gravimetric analysis (TG) and differential thermal gravimetric (DTG), samples calcined at different temperatures (350, 500 and 700°C) were characterized by X-ray diffraction (XRD), field emitting scanning electron microscopy (FESEM), transmission electron microscopy (TEM), cyclic voltammogram and charge-discharge cycling tests. A phase transition during the calcination process was observed from the XRD patterns. And the sample calcined at 500°C had a distribution of diameters around 20 nm and exhibited large capacity and good high rate capability. The well reversible cyclic voltammetric results of both electrodes indicated enhanced electrochemical kinetics for lithium insertion. It was found that the Li4Ti5O12 anode material prepared through gel-hydrothermal process, when being cycled at 8 C, could preserve 76.6% of the capacity at 0.3 C. Meanwhile, the discharge capacity can reach up to 160.3 mAh·g,1 even after 100 cycles at 1 C, close to the theoretical capacity of 175 mAh·g,1. The gel-hydrothermal method seemed to be a promising method to synthesize LTO nanoparticles with good application in lithium ion batteries and electrochemical cells. [source]

Perylene Nanoparticles Prepared by Reprecipitation Method

CHINESE JOURNAL OF CHEMISTRY, Issue 2 2002
Xue-Hai Ji
Abstract Perylene nanoparticles with different sizes were prepared by reprecipitation method. It is found that the nanoparticles show size-dependent optical property. Electron diffraction patterns indicate that all the nanoparticles of different sizes are in crystalline state. The rapid growth of the nanoparticles during the aging process could be slowed down effectively by the addition of cationic or anionic surfactants. [source]