Carrier Redistribution in van der Waals Nanostructures Consisting of Bilayer Graphene and Buckybowl: Implications for Piezoelectric Devices

The geometric and electronic structures of a complex nanomaterial consisting of a sumanene (C21H12) and bilayer graphene are investigated in terms of the molecular conformation between the layers using density functional theory. Our calculations indicated that the sumanene-intercalated bilayer graphene is the key material for designing the piezoelectric devices capable of supplying an electric energy density of 30 μWh/cm2. The dipole moment of a bowl-shaped hydrocarbon sumanene induces an electrostatic potential difference between the graphene layers, resulting in charge transfer between the graphene layers. Holes and electrons are induced on the graphene layers located at the convex and edge sides of sumanene, respectively, with the densities of 4.4 × 1012 and 6.6 × 1011/cm2. Furthermore, the two-dimensional nanospacing between the graphene layers changes the molecular conformation of sumanene from a bowl to flat structure at 0.8 GPa.