Novel self-assembly can tune the electronic properties of graphene
In what could prove to be a significant advance in fabricating new technologies, scientists discovered a new self-assembly mechanism that surprisingly drives negatively charged molecules to clump together to form islands when graphene is supported by an electrical insulator. Under these conditions, different charge interactions are not diminished, as they are when graphene is supported by a metallic substrate. At low concentrations, individual adsorbed molecules repel each other, but with increasing concentration, the molecules form two-dimensional islands. It was determined by theory that the flow of extra electrons into the islands from graphene keeps the molecules together. The electronic driving forces and stabilization energies are sufficient to overcome the repulsion between the negative charges.