ChemInform Abstract: Synthesis of Highly Crystalline and Monodisperse Maghemite Nanocrystallites Without a Size-Selection Process.

School of Chemical Engineering and Institute of Chemical Processes, Seoul National University, Seoul 151-744, Korea.
Journal of the American Chemical Society (Impact Factor: 12.11). 04/2010; 123(51):12798-801. DOI: 10.1002/chin.200217234
Source: PubMed


The synthesis of highly crystalline and monodisperse gamma-Fe(2)O(3) nanocrystallites is reported. High-temperature (300 degrees C) aging of iron-oleic acid metal complex, which was prepared by the thermal decomposition of iron pentacarbonyl in the presence of oleic acid at 100 degrees C, was found to generate monodisperse iron nanoparticles. The resulting iron nanoparticles were transformed to monodisperse gamma-Fe(2)O(3) nanocrystallites by controlled oxidation by using trimethylamine oxide as a mild oxidant. Particle size can be varied from 4 to 16 nm by controlling the experimental parameters. Transmission electron microscopic images of the particles showed 2-dimensional and 3-dimensional assembly of particles, demonstrating the uniformity of these nanoparticles. Electron diffraction, X-ray diffraction, and high-resolution transmission electron microscopic (TEM) images of the nanoparticles showed the highly crystalline nature of the gamma-Fe(2)O(3) structures. Monodisperse gamma-Fe(2)O(3) nanocrystallites with a particle size of 13 nm also can be generated from the direct oxidation of iron pentacarbonyl in the presence of oleic acid with trimethylamine oxide as an oxidant.

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Available from: Jongnam Park, Aug 24, 2015
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    • "Iron oxide nanoparticles including magnetite (Fe 3 O 4 ), hematite (í µí»¼-Fe 2 O 3 ), maghemite (í µí»¾-Fe 2 O 3 ), goethite (í µí»¼-FeOOH), and akaganeite (í µí»½-FeOOH) nanoparticles have attracted enormous attention due to their interesting properties678910. Many methods have been developed for the preparation of í µí»¾-Fe 2 O 3 magnetic nanoparticles, including coprecipitation[11], a gas-phase reaction technique[12], direct thermal decomposition[13], thermal decomposition-oxidation[14], sonochemical synthesis[15], a microemulsion technique[16], hydrothermal synthesis[17], a vaporization-condensation method[18], and a sol-gel approach[19]. Reactions for the synthesis of oxide nanoparticles using the coprecipitation method can be grouped into two categories . "
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    ABSTRACT: SnS of orthorhombic (OR) and metastable (SnS) phases were synthesized by using a simple and facile colloidal method. The tin precursor was synthesized using tin oxide (SnO) and oleic acid (OA), while the sulfur precursor was prepared using sulfur powder (S) and oleyamine (OLA). The sulfur precursor was injected into the tin precursor and the prepared SnS nanocrystals were precipitated at a final reaction temperature of 180 °C. The results show that hexamethyldisilazane (HMDS) can be successfully used as a surfactant to synthesize monodisperse 20 nm metastable SnS nanoparticles, while OR phase SnS nanosheets were obtained without HMDS. The direct bandgap observed for the metastable SnS phase is higher (1.66 eV) as compared to the OR phase (1.46 eV). The large blueshift in the direct bandgap of metastable SnS is caused by the difference in crystal structure. The blueshift in the direct band gap value for OR-SnS could be explained by quantum confinement in two dimensions in the very thin nanosheets. SnS thin films used as a photo anode in a photoelectrochemical (PEC) cell were prepared by spin coating on the fluorine-doped tin oxide (FTO) substrates. The photocurrent density of the SnS (metastable SnS)/FTO and SnS (OR)/FTO are 191.8 μA/cm2 and 57.61 μA/cm2 at an applied voltage of − 1 V at 150 W, respectively. These narrow band gap and low cost nanocrystals can be used for applications in future optoelectronic devices.
    No preview · Article · Oct 2015 · Thin Solid Films
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    • "The decomposition of iron pentacarbonyl in the presence of oleic acid is a well known method for Fe-NP formation[23]. Ferrocene has also been shown to decompose and form a carbon shell around the iron nanoparticles and has shown to exhibit novel structures[41]. "
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    Full-text · Article · Apr 2015 · Carbon
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