Characterization of Carbon Structures produced by Graphene Self-Assembling

Low-dimensional carbon-based materials, in particular graphenic 2D-carbon structures, were produced from colloidal dispersions of graphitic nanoflakes obtained from SWCNT disruption using high-shear mixing and/or treatments in sulfonitric acid mixtures both at room and high temperature. Depending on the unzipping procedures, different kinds of re-organization are found to occur, mainly evidenced by selected area electron diffraction (SAED) and by reflection high energy electron diffraction (RHEED) analyses coupled to transmission and scanning electron microscopy observations. Such combined investigations in the real and reciprocal space represent an enabling gate able to provide structural information at the nanoscale on the clustering of graphitic layers in platelets or/and assembly into highly ordered (single-crystal) nano-sheets. A different carbon phase with an orthorhombic cell and symmetry Cmma has been detected by SAED and by RHEED analyses. This work focused on the results achieved through such characterization methodology, evidencing the presence of different self-assemblies of graphene depending on the rotational and/or translational stacking faults of the hexagonal basal planes. Overall, the proposed methodology represents a reliable tool for controlling the self-assembled structures of low dimensional materials, as those ones of graphene-based structures with tailored dimensions, technologically important because of its strong correlation with electronic structure.