A series of polished and unpolished $s{p}^2$-nanostructured carbons “nanographites” obtained from the pyrolysis of various precursor types have been systematically studied by both Raman spectroscopy and x-ray diffraction. The ratio between the intensities of the disorder-induced $D$ band and the first-order graphite $G$ band ($I_D$/$I_G$) commonly used up to now to estimate the “crystallite” diameter $L_a$ displays, in the case of polished graphitized $s{p}^2$ carbons, clear spatial heterogeneities and can lead to the overestimation of the intrinsic structural disorder. The full width at half maximum of the $G$ band, which is shown to be insensitive to the polishing process, exhibits a linear dependence on the mean “crystallite” diameter [FWHM($G$) $=$ 14 $+$ 430/$L_a$] and therefore can be used for an accurate structural characterization of these nanographites.

• Received 19 July 2012

DOI:https://doi.org/10.1103/PhysRevB.86.134205