A structural insight into mechanical strength of graphene-like carbon and carbon nitride networks

Abstract

Graphene, one of the strongest materials ever discovered, triggered the exploration of many 2D materials in the last decade. However, the successful synthesis of a stable nanomaterial requires a rudimentary understanding of the relationship between its structure and strength. In the present study, we investigate the mechanical properties of 8 different carbon-based 2D nanomaterials by performing extensive density functional theory calculations. The considered structures were just recently either experimentally synthesized or theoretically predicted. The corresponding stressstrain curves and elastic moduli are reported. They can be useful in training force field parameters for large scale simulations. A comparative analysis of these results revealed a direct relationship between atomic density per area and elastic modulus. Furthermore, for the networks that have an armchair and a zigzag orientation, we observed that they were more stretchable in the zigzag direction than the armchair direction. A critical analysis of the angular distributions and radial distribution functions suggested that it could be due to the higher ability of the networks to suppress the elongations of the bonds in the zigzag direction by deforming the bond angles. The structural interpretations provided in this work not only improve the general understanding of a 2D material's strength but also enables us to rationally design them for higher qualities.3

Metamorphosis in carbon network: From penta-graphene to biphenylene under uniaxial tension

“…A unidirectional strain was applied while the box size in the transverse direction was adjusted so that the stress in that direction was close to Our recent study on several graphene-like carbon and carbon nitride networks demonstrated proportionality between elastic modulus and atomic density (number of atoms divided by area). [51] Graphene which has a higher atomic density than biphenylene is expected to be stronger, which is confirmed by the results reported here.…”

First principles investigation of nitrogenated holey graphene

“…The calculated results also show that the bond lengths of N-C and C-C will increase with the strain changing from compressive strain to tensile strain. This change in the bond length indicates that NHG exhibits very good elastic characteristics, which is in agreement with previous investigation [10,11]. The defect concentration is inversely proportional to exponential functional of its formation energy [33].…”

Atomistic insights into the anisotropic mechanical properties and role of ripples on the thermal expansion of h-BCN monolayers

“…A similar pattern of bond angles and lengths has been reported in the case of other 2D materials such as biphenylene, phagraphene and nitrogenated holey graphene. 45 We attribute the high stretchability along the armchair direction to the signicant widening of the bond lengths and angles in the h-BCN system. We also found that certain stages of deformation in h-BCN involve the formation of defects, cracks, and the breaking of bonds and that the edges of the h-BCN material are easily affected by the deformation, as shown in Fig.…”