Strain-induced charge transfer and polarity control of a heterosheet comprising C60 and graphene

Using density functional theory combined with the effective screening medium method, the energetics and electronic structure of a C60 molecular sheet adsorbed on graphene were studied in terms of biaxial strains. The optimum spacing and interlayer interaction monotonically decreases and increases, respectively, with an increasing biaxial tensile strain. The biaxial compressive strain induces electron transfer from the graphene to C60 at a 2% lateral compression, leading to an all-carbon charge transfer complex. The heterosheet possesses an intrinsic dipole moment along the graphene-to-C60 molecular layer direction.