Surface on Surface. Survey of the Monolayer Gold–Graphene Interaction from Au₁₂ and PAH via Relativistic DFT Calculations

Abstract

Gold-graphene interaction at the interface is evaluated through different polyaromatic hydrocarbons (PAH), accounted by C 6 H 6 , C 24 H 12 , C 54 H 16 and C 96 H 18 , focusing into different energetic terms related to the overall interaction. Our results characterize the neutral gold-PAH interaction nature with 45% of dispersion character, 35% of electrostatic, and 20% of covalent character, suggesting that moderate van der Waals character is mostly involved in the interaction, which increases according to the size of the respective PAH. The resulting surface charge distribution in the graphene model is a relevant parameter to take into account, since the ability of the surface charge to be reorganized over the polycyclic structure in both contact and surrounding regions is important in order to evaluate interactions and different interacting conformations.Our results suggest that for a Au 12 contact surface of radius 4.13 Å, the covalent, electrostatic and dispersion character of the interaction are effectively accounted in a graphene surface of about 6.18 Å, as given by circumcoronene, depicting a critical size where the overall interaction character can be accounted.

Molecular planting of a single organothiol into a “gap-site” of a 2D patterned adlayer in an electrochemical environment

“…The phase transition under controlled potential was thus a transition to a metastable adlayer on Au(111). Indeed, according to density functional theory (DFT) calculations for PAH molecules and a Au surface, charge transfer occurs from the Au surface to the PAH molecules, 60 suggesting that the surface charge density can be precisely modulated by the applied potential at the electrochemical interface and appears to contribute not only to the molecule–substrate interaction but also to the interactions among the molecules. PAHs are generally neutral, but they have π electrons.…”

“…According to a recent theoretical calculation, PAHs such as hexabenzocoronene adsorb onto the bridge site rather than the top site of the Au atoms in Au 12 clusters. 60 …”

Aggregation and support effects in the oxidation of fluxional atomic metal clusters. The paradigmatic Cu5 case

“…For the sake of comparison, a previous work has shown that the PAH circumcoronene (C 54 H 18 ) is large enough to model the graphene-Au 12 interaction. 34 2.1.2 Density functional theory and ab initio calculations. Dispersion-corrected density functional theory (DFT) has been applied to study the adsorption of up to 8 O 2 molecules on bare Cu 5 and Cu 5 -Cu 5 systems as well as circumpyrenesupported Cu 5 clusters.…”

“…For the sake of comparison, a previous work has shown that the PAH circumcoronene (C 54 H 18 ) is large enough to model the graphene–Au 12 interaction. 34…”

“…The electrons of the C(2s, 2p) and Cu(3d, 4s) orbitals were treated explicitly as valence electrons using plane wave basis sets with a kinetic energy cutoff large enough to get converged interaction energies. For the sake of comparison, a previous work has shown that the PAH circumcoronene (C 54 H 18 ) is large enough to model the graphene-Au 12 interaction 34.…”