Journal: Journal of Nanomaterials

Abbreviation

Publisher

Hindawi

Journal Volumes

ISSN

1687-4129
1687-4110

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2011 - 20132
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Publications 1 - 2 of 2
  • Towards a Reproducible Synthesis of High Aspect Ratio Gold Nanorods
    Item type: Journal Article
    Koeppl, Susanne; Solenthaler, Christian; Caseri, Walter; et al. (2011)
    Journal of Nanomaterials
    The seed-mediated method in presence of high concentrations of CTAB is frequently implemented in the preparation of high aspect ratio gold nanorods (i.e., nanorods with aspect ratios of 5 or more); however, the reproducibility has still been limited. We rendered the synthesis procedure simpler, decreased the susceptibility to impurities, and improved the reproducibility of the product distribution. As a result of the high aspect ratios, longitudinal plasmon absorptions were shifted up to very high absorption maxima of 1955 nm in UV-vis-NIR spectra (since this band is completely covered in aqueous solution by the strong absorption of water, the gold species were embedded in poly(vinyl alcohol) films for UV-vis-NIR measurements). Finally, the directed particle growth in (110) direction leads to the conclusion that the adsorption of CTAB molecules at specific crystal faces accounts for nanorod growth and not cylindrical CTAB micelles, in agreement with other observations.
  • Carbon Micronymphaea: Graphene on Vertically Aligned Carbon Nanotubes
    Item type: Journal Article
    Choi, Jong Won; Youn, Seul Ki; Park, Hyung Gyu (2013)
    Journal of Nanomaterials
    This paper describes the morphology of carbon nanomaterials such as carbon nanotube (CNT), graphene, and their hybrid structure under various operating conditions during a one-step synthesis via plasma-enhanced chemical vapor deposition (PECVD). We focus on the synthetic aspects of carbon hybrid material composed of heteroepitaxially grown graphene on top of a vertical array of carbon nanotubes, called carbon micronymphaea. We characterize the structural features of this unique nanocomposite by uses of electron microscopy and micro-Raman spectroscopy. We observe carbon nanofibers, poorly aligned and well-aligned vertical arrays of CNT sequentially as the growth temperature increases, while we always discover the carbon hybrids, called carbon micronymphaea, at specific cooling rate of 15°C/s, which is optimal for the carbon precipitation from the Ni nanoparticles in this study. We expect one-pot synthesized graphene-on-nanotube hybrid structure poses great potential for applications that demand ultrahigh surface-to-volume ratios with intact graphitic nature and directional electronic and thermal transports.
Publications 1 - 2 of 2