Closed π-electron network in large polyhedral multi-shell carbon nanoparticles

A. I. Shames, I. Felner, V. Yu Osipov, E. A. Katz, E. Mogilko, J. Grinblat, A. M. Panich, V. P. Belousov, I. M. Belousova, A. N. Ponomarev

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

High Resolution Transmission Electron Microscopy (HRTEM) reveals a polyhedral multi-shell fullerene-like structure of astralen carbon nanoparticles. The polyhedra consist of large flat graphitic faces connected by defective edge regions with presumably pentagon-like structure. The faces comprise a stacking of 20-50 planar graphene sheets with inter-sheet distance of ̃0.340 nm. Average sizes of the particles and their flat faces are ̃40 nm and ̃15 nm, respectively. Astralen particles are suggested to have defect-free sp2 flat faces and all defects condense at their polyhedral edges. Multi-frequency Electron Paramagnetic Resonance (EPR) spectra of polycrystalline astralen samples reveal two main signals: a very broad signal with AHpp > 1 T and an asymmetric relatively narrow signal that consists of two Lorentzian components in g = 2.00 region. The intensities of all X-band EPR signals show no changes on decreasing temperature down to T = 4 K. Magnetic susceptibility demonstrates strong temperature dependent orbital diamagnetism. All unusual magnetic features of astralen are attributed to prevalent itinerant spins.

Original languageEnglish
Pages (from-to)41-48
Number of pages8
JournalNanoscience and Nanotechnology Letters
Volume3
Issue number1
DOIs
StatePublished - 1 Feb 2011

Keywords

  • Carbon onions
  • Delocalized electrons
  • Magnetic resonance
  • Magnetic susceptibility
  • Multi-shell
  • Polyhedral nanoparticles

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