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.