Graphene is a promising candidate for transparent conducting electrode applications in flexible optoelectronic devices.However,the conductivity of graphene is much lower than that of the conventional indium tin oxide(ITO),which hinders the extensive application of the material in light-emitting diodes or organic solar cells.Recent studies have demonstrated that the attachment of organic molecules,such as tetracyanoquinodimethane(TCNQ)and tetrafluoro-tetracyanoquinodimethane(F4-TCNQ),to graphene is an effective way to enhance its conductivity to the level of ITO.It is commonly acknowledged that some important properties of function interfaces depend on geometrical atomic arrangements and also the interactions that exist among constituent atoms or molecules; consequently,the accurate prediction of energetics and structures for aromatic molecules on substrates are highly demanded [1-3].In this work,we employ density-functional calculations including an accurate description of the many-body dispersion(MBD)interactions [4,5],to systematically study the interactions of TCNQ and F4-TCNQ with graphene at different coverage.We find that the MBD computed adsorption energies are consistently lower than those from the pairwise method,such as PBE+vdW [3],due to the accurate capture of the screening effects in the former approach.Remarkably,the adsorption energies significantly decrease by 20%,no matter whether at the high or the low coverage.In contrast to conventional notion that many-body effects would be more promising to highly assembled surfaces,our calculations clearly demonstrate that MBD contributes less in high-coverage systems.We attribute this “abnormal” observation to the anisotropic polarizability from the MBD method.