Theoretical characterization of the TTF/Au (1 1 1) interface: STM imaging, band alignment and charging energy

A detailed density functional study is performed to analyze the TTF/Au (1 1 1) interface, including the effect of the molecular charging energy on the transport gap. Theoretical STM calculations are carried out, and compared with recent STM experimental evidence, for a dilute TTF/Au (1 1 1) structure in order to validate the interface geometry used in our calculations. We show that the alignment between the metal and the organic levels is mainly controlled by the charge transfer between the two materials, as determined by the difference between the molecule Charge Neutrality Level (CNL), and the initial Fermi level. The calculated transport gap is 4.1 eV, and the CNL is found close to the LUMO level, located about 0.7 eV from vacuum.

Grapical abstractFigure optionsDownload as PowerPoint slideHighlights
► A detailed DFT study is performed to analyze the TTF/Au (1 1 1) interface.
► Charging energy effects are accounted in the molecule transport energy gap.
► Important electronic interfacial properties are calculated across coverages.
► Theoretical STM calculations are successfully compared with recent STM experiments.
► This excellent agreement validates the interface geometry used in our calculations.