Metal–semiconductor transition in bilayer graphene by bowl inversion of monofluorosumanene

The bowl-shaped hydrocarbon molecule, monofluorosumanene (C21H11F), can act as a molecular switch to control the carrier density of bilayer graphene by flipping its conformation. Our calculations indicate that monofluorosumanene, in which F atom is located outside the curved C–C network (exo-F molecular conformation), induces electron and hole co-doping of 1.5 × 1013 cm−2 in monofluorosumanene-intercalated bilayer graphene because of a large dipole moment normal to the molecular plane of the monofluorosumanene. The intercalated monofluorosumanene does not affect the electronic structure of bilayer graphene when the F atom is located inside the curved C–C network (endo-F conformation) owing to a small out-of-plane dipole moment. The application of an external electric field across the graphene layers promotes bowl inversion between endo-F and exo-F molecular conformations because of the low activation barrier (approximately 800 meV) between these two conformations and the dipole moment normal to the molecular plane of the exo-F conformation.