Supramolecular Assembly through Interactions between Molecular Dipoles and Alkali Metal Ions

Establishing a way to fabricate well‐ordered molecular structures is a necessary step toward advancement in organic optoelectronic devices. Here, we propose to use interactions between electric dipoles of molecules and alkali metal ions to form a well‐developed homogeneous monolayer of diarylethene molecules on the Cu(111) surface with the aid of NaCl co‐deposition. Scanning tunneling microscopy and density functional theory calculation results indicate that the formation of a row‐type structure occurs as a result of interactions between the Na+ ions and the diarylethene molecular dipoles, drastically changing the adsorption configuration from that without Na+. Only with Na+: Diarylethene molecules are arranged into a well‐ordered film on Cu(111) through supramolecular assembly with the aid of NaCl co‐deposition. Interactions between molecular dipoles and Na+ cations are the driving force for the superstructure formation.