Bilayer graphenes with antidots: structures, properties and applications

Binding Free Energy Calculations of Bilayer Graphenes Using Molecular Dynamics

Bilayer graphenes are dimeric assemblies of single graphene layers bound together by π-complexation interactions. Controlling these assemblies can be complicated, as the layered compounds disperse in solvents or aggregate into higher columnar configurations and clusters. One way to assess the interactions that contribute to the stability of the layered compounds is to use molecular simulation. We perform pulling molecular dynamics on bilayer graphenes with different sizes and obtain the normal and shear force profiles of dissociation. We generate pathways of dissociation along the two directions and calculate the binding free energies of the structures with umbrella sampling simulations. We show that the dissociation process is direction-dependent. Along the shear direction, we compute the same free energy for the different samples, which validates the consistency of our simulations. We notice that the dissociation is less adiabatic on the normal than the shear direction, having an entropic contribution to the Gibbs energy. This contribution is more enhanced for the larger bilayer graphenes.

Atomic Structure and Mechanical Properties of Twisted Bilayer Graphene

We studied the atomic structure and mechanical properties of twisted bilayer graphene with a different twist angle using molecular dynamic simulations. The two layers are corrugated after energy minimization. We found two different modes of corrugation. The mechanical properties are tested both in-plane and perpendicular to the plane. The in-plane properties are dominated by the orientation of graphene. The perpendicular properties depend on the twist angle, as the larger the twist angle, the higher the intrinsic strength.