Predictive first-principles modeling of complex inorganic/organic interfaces: PTCDA on Au(111)

Understanding the properties of hybrid inorganic/organic systems has implications in both fundamental science and technology. An ab-initio modeling of these interfaces require efficient electronic-structure methods that capture accurately covalent and non-covalent interactions and an atomistic model that includes complex adsorption configurations and accurate surface representation. We present a predictive characterization of the structure and stability of perylenetetracarboxylic dianhydride (PTCDA) adsorbed on Au(111) within density-functional theory. Our calculations include collective many-body effects in the modeling of non-covalent interactions and a quantification of the self-interaction error in the adsorption energy of the system. We address effects due to single molecule/monolayer surface coverage and the role of the experimentally observed 22 × √3 surface reconstruction. Our approach yields an adsorption geometry in agreement with experiments within 0.1 Å and explains a difference of ≈ 0.5 eV observed in the adsorption energy of the system between atomic-force microscope and temperature-programmed desorption experiments. Our work shows that the inclusion of all relevant collective effects yields predictive power in the first-principles simulation of complex interfaces.