We present an investigation of the structural and electronic properties of an ordered grain boundary (GB) formed by separated pentagon-heptagon pairs in single-layer graphene/SiO2 using scanning tunneling microscopy/spectroscopy (STM/STS), coupled with density functional theory (DFT) calculations. It is observed that the pentagon-heptagon pairs, i.e., (1,0) dislocations, form a periodic quasi-o...

Defects are common but important in graphene, which could significantly tailor the electronic structures and physical and chemical properties. In this study, the density functional theory (DFT) method was applied to study the electronic structure and catalytic properties of graphene clusters containing various point and line defects. The electron transfer processes in oxygen reduction reaction ...

From the pentagon onwards, the area of the regular convex polygon with n sides and unit diameter is greater for each odd number n than for the next even number n + 1. Moreover, from the heptagon onwards, the difference in areas decreases when n increases. Similar properties hold for the perimeter. A new proof of a result of Reinhardt follows.

We study the energy spectrum and persistent current of charge carriers confined in a graphene quantum ring geometry radius $R$ width $w$ subjected to magnetic flux. consider case where crystal symmetry is locally modified by replacing hexagon pentagon, square, heptagon or octagon. To model this type defect we include appropriate boundary conditions for angular coordinate. The electrons are fini...

The feasibility of employing azulene-like molecules as a new type of high performance substitution-free molecular rectifier has been explored using NEGF-DFT calculation. The electronic transport behaviors of metal-molecule-metal junctions consisting of various azulene-like dithiol molecules are investigated, which reveals that the azulene-like molecules exhibit high conductance and bias-depende...

The purity of graphene samples is of crucial importance for their experimental and practical use. In this regard, the detection of the defects is of direct relevance. Here, we show that structural defects in graphene samples give rise to clear signals in the vibrational density of states (VDOS) at specific peaks at high and low frequencies. These can be used as an independent probe of the defec...

Helical metal-organic frameworks (MOFs) were used as templates or precursors to fabricate helical carbon nanorods (HCNRs) for the first time. contains many topological defects such pentagonal heptagonal carbons, which have potential facilitate oxygen reduction reactions (ORR). HCNRs show more positive onset/half-wave potentials and higher limited current density than straight (SCNRs). They also...

Stone-Wales operators interchange four adjacent hexagons with two pentagon-heptagon 5|7 pairs that, graphically, may be iteratively propagated in the graphene layer, originating a new interesting structural defect called here Stone-Wales wave. By minimization, the Wiener index topological invariant evidences a marked anisotropy of the Stone-Wales defects that, topologically, are in fact prefera...

We present a mechanism of high-temperature sublimation of carbon nanotubes that does not destroy their ordered makeup even upon significant loss of mass. The atoms depart to the gas phase from the pentagon-heptagon dislocation cores, while the bond disruption is immediately repaired, and the 5|7 seamlessly propagate through the lattice. This explains a broad class of unsettled phenomena when at...

ABSTRACT Several works on nonclassical fullerenes with heptagons have mainly considered the case with just one heptagon. In this context the isolated pentagon rule is not satisfied. The study of nonclassical fullerenes is important because some of them are more stable than the corresponding classical isomers with the same number of pentagonal bonds. We present several nonclassical fullerenes wi...