The effect of molecular decoration on formation of curved and twisted graphene

Abstract

The formation of curved and twisted ThMoB4-type sheet graphene (TSG) surface via adsorption of the ethylene carbonate(EC) solvent molecule has been theoretically investigated. The calculation has been performed by one of the extended self-consistent-charge density-functional tight-binding methods named as GFN1-xTB. During the calculation, six different possibilities of decorations for EC molecule have been tried. These decorations are considered thermodynamically stable for TSG surface. We obtained the optimized lattice parameters, surface areas and adsorption energies (Ead) for six surface decorations. We reveal that the value of Ead is the main reason for the difference in the formation of the surface. The zigzag configuration of the graphene results in the positive and large Ead value of +4.4 eV leading to the curved surface which is bending toward the adsorbed molecule. In the case of adsorption of EC which is decorated at the armchair site, the surface is perfectly twisted due to the Ead value of -2.45 eV. Furthermore, the change in UV–vis/IR spectrum concerning the formation of the structure has been analyzed. Our results claim that this type of graphene structure can be a candidate for the application of chemical or biological sensing.