The graphene flakes were semi-infinite ribbons with serrated edges, composed of 9234 atoms, which were initial created using Jmol . The interaction between flakes was achieved by imposing periodic boundary conditions, such that the nanoribbon repeats itself along the directions perpendicular to the edges, thus allowing for edge-edge interactions. Additionally, we performed similar calculations for a four-layer graphene flake in vacuum, for comparison between thin sheet clusters and infinitely thick ones.