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Samples of thermally reduced graphene oxide are studied using differential cross sections for photoelectron inelastic energy losses. We compare different procedures for recovering cross sections from the photoelectron energy spectra resulting from multiple inelastic scattering. It is shown that the cross section for inelastic energy losses (which uniquely characterizes allotropes of carbon) in the sample containing the minimal amount of carbon oxides corresponds the best to pyrolytic graphite. [ABSTRACT FROM AUTHOR]

The dynamics of X-ray photoelectron emission spectra is studied in the region of the 1s carbon line with increasing treatment temperature for graphene-oxide samples. It is established that, as the degree of oxide reduction increases, the role of the mechanism related to energy losses for the excitation of π-plasmon oscillations produced in the presence of sp2 bonds in the carbon sample increases. Spectral analysis shows that the π-plasmon peak is manifested in the spectra of samples annealed at temperatures exceeding 200°C. When determining the differential cross sections for inelastic electron scattering, the difference between the energy losses in the surface sample layers and the homogeneous bulk located far from the surface is taken into account. The obtained spectra are compared with those of multilayer graphene and pyrolytic graphite. It is shown that the analysis of graphene oxide using X-ray photoelectron spectroscopy gives a picture on a nanometer scale. The obtained data can differ noticeably from the Raman spectroscopy data corresponding to the millimeter scale. [ABSTRACT FROM AUTHOR]

Nanocarbon composites present a new type of nanomaterials consisted of electric conducting carbon nanoparticles and a non-conducting matrix. A typical example of such composites is a polymer matrix doped with carbon nanotubes (CNT). Due to a high aspect ratio of nanotubes insertion of very small quantity of CNT (on the level of 0.01%) promotes the percolation transition resulting in an enhancement of the conductivity of the material by 10–12 orders of magnitude. Another type of nanocarbon composite is a film consisted of partially reduced graphene oxide (GO) produced as a result of thermal reduction of graphite oxide material. Distinctive peculiarity of both types of nanocomposites relates to the dependence of the specific resistivity of the materials on the applied voltage. Such a behavior is caused by non-ideal contacts between neighboring carbon particles involving into the composite. The resistance of this contact depends drastically on the intra-contact field, which promotes the dependence of the material resistivity on the applied voltage. The model description of such a non-linear dependence has been presented. The calculation results are compared with both literature data and the measured data obtained for reduced GO thermally treated at various temperatures. [ABSTRACT FROM AUTHOR]