First-principles study on the interlayer adhesion in graphene/organic molecule/graphene van der Waals heterostructures

Abstract

Van der Waals heterostructures can broadening materials design range however manufacturing them still in open question. Meanwhile since property of graphene-based device can be tuned by organic molecules, combining them has large potential in utilizing them. Here Interlayer adhesion energy which can viewed as structural stability, formation energy, and interlayer interaction mechanism of graphene/organic molecule/graphene (organic molecule= pentacene, PFP, PTCDA, F16CuPc, and F4-TCNQ) are investigated using density functional theory. All structures have negative formation energy and interlayer adhesion energy per area is G/pentacene/G= 1.557 eV/nm^2, G/PFP/G= 1.536 eV/nm^2, G/PTCDA/G= 1.554 eV/nm^2, G/F16CuPc/G= 1.592 eV/nm^2, G/F4-TCNQ/G= 1.630 eV/nm^2. Interaction mechanism of G/F4-TCNQ/G is van der Waals + charge transfer whereas the others have only van der Waals characteristic. Interlayer adhesion energy is smaller comparing to that of bulk layered materials.