Adsorption of squaraine molecules to Au(111) and Ag(001) surfaces.

The adsorption of anilino squaraines, an important chromophore for the use in organic solar cells, to Ag(001) and Au(111) has been studied with scanning tunneling microscopy. Self-assembly into square building blocks with eight molecules per unit cell is revealed on the Ag surface, while no ordering effects occur on gold. The squaraine-silver interaction is mediated by the carbonyl and hydroxyl oxygens located in the center of the molecule.

Understanding molecular self-assembly of a diol compound by considering competitive interactions.

With a combination of scanning tunneling microscopy and density functional theory, effects on molecular self-assembly involving two distinct chemical groups were investigated. We analyzed the influence of the individual functional units in the adsorbate and extracted the dominating contributions to the adsorption behaviour. The viability of such a systematic approach to study self-assembled structures by considering the interplay between substrate effects and molecular design is demonstrated.