Optical manifestations of the condensation of topological defects in continuous layer multishell carbon nanoparticles

We report the observation and the explanation of the famous $220\mathrm{nm}$ spectral feature in UV absorption from continuous layer multishell carbon nanoparticles. Historically, attempts to find this feature in carbon allotropes led to the discovery of the ${\mathrm{C}}_{60}$ fullerene. We discerned the physical origin of this feature to be the well-defined pentagonal corner defects in polyhedral multilayer carbon nanoparticles. These new topological columnar defects should have large influence on the electronic properties of nanomaterials and are worthwhile further detail studying.

Figure 1

The geometry of different type SCNPs seen from TEM images. (a),(b) The apex angle $112.88°$ for 5MRCs is marked with white lines; (c) the pentagon and heptagon induced angles are marked with letters $\mathrm{P}$ and $\mathrm{H}$, respectively.

Figure 2

UV absorption spectra for SCNPs: (a) on quartz plates; (b) in water solutions; (c) ballmilled for 2 hours. The vertical lines show the position of $220\mathrm{nm}$, $260\mathrm{nm}$, and $300\mathrm{nm}$ features. The upturns in absorbance seen in (b) and (c) for the wavelengths less than $200\mathrm{nm}$ indicate the presence of some amount of flat graphene sheets with around $6\mathrm{eV}$ graphite plasmon especially pronounced for ballmilled samples where such sheets inevitably appear in debris. We proved it by comparing the spectra with the ones from acetylene soot with numerous BSUs. The soot shows only the upturn with no other features.

Figure 3

Raman spectra from SCNPs. (a) a higher isolation of SCNPs with SDS brings a higher fluorescence intensity, which buries the characteristic Raman features at 1350 and $1590{\mathrm{cm}}^{-1}$; (b) a recalculated fluorescence spectrum from the Raman spectrum obtained with $514.5\mathrm{nm}$ $\mathrm{Ar}$-ion laser from isolated SCNP compared with a part of the light absorption spectrum for SDS isolated SWNTs from Ref. 16.