Characterization of carbon structures produced by graphene self-assembly

Abstract

Low-dimensional carbon-based materials, in particular two-dimensional graphenic carbon structures, have been produced from single-walled carbon nanotube disruption using high-shear mixing and/or treatments in sulfonitric acid mixtures at both room and high temperature. Among other two-dimensional graphenic carbon structures, colloidal dispersions of graphenic nanoflakes have been obtained. Different structural arrangements, resulting from the reorganization of carbon because of the disruption procedures applied, were observed through selected area electron diffraction (SAED) and through reflection high-energy electron diffraction (RHEED) analyses coupled to transmission and scanning electron microscopy observations. Such combined investigations in the real and reciprocal space provided structural information at the nanoscale on the clustering of graphene layers in nanoplatelets or/and on their assembly into highly ordered (single-crystal) nanosheets. Furthermore, a different carbon phase exhibiting an orthorhombic cell with Cmma symmetry has been detected by SAED and RHEED analyses. In addition, a variety of self-assemblies of hexagonal basal planes have been observed to occur as the result of their different rotational and/or translational stacking faults. Overall, the reported results contribute to define the conditions for a controlled self-assembly of graphene-based structures with tailored dimensions, which is an important technological challenge, as their structure at the nanoscale dramatically affects their electrical properties

Investigation of Structure and Chemical Composition of Carbon Nanofibers Developed From Renewable Precursor

“…The smallest diffraction ring in the SAED pattern was assigned to the (002) planes. Notably, a prominent broadening effect was observed, which indicated loss of periodicity along the sheetstacking direction of the graphitic structure (Matassa et al, 2014). Moreover, diffraction rings corresponding to (101) and (112) planes were detected, and the corresponding interplanar distances were calculated.…”

Structural and morphological peculiarities of hybrid Au/nanodiamond engineered nanostructures

“…Besides diamond, no further reflections are present in the EDP, excluding a detectable presence of graphite, which can be identified based on different d- spacings. In particular, even the strongest diffraction graphite reflection (corresponding to the interplanar distance d 0002 = 0.3354 nm) is absent ( Table S1 ) 45 . As far as morphology is concerned, the HR-TEM in Fig.…”

A Deep Look Into Erionite Fibres: an Electron Microscopy Investigation of their Self-Assembly

“…The area of sample ED (region II of Fig. 1a ) has also been characterised by electron diffraction technique in order to establish its crystallographic features at nanometric scale 36 . The corresponding Selected Area Electron Diffraction (SAED) pattern shows a complex, albeit regular rectangular array of diffraction spots and, along one radial direction, high order intense reflections with diffraction diffuse streaks can be noticed ( Fig.…”