Determination of crystallite size in polished graphitized carbon by Raman spectroscopy

A series of polished and unpolished sp²-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 (ID/IG) commonly used up to now to estimate the ``crystallite'' diameter Lₐ displays, in the case of polished graphitized sp² 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/Lₐ] and therefore can be used for an accurate structural characterization of these nanographites.