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(+).