Scanning Tunneling Microscope Tip-Induced Formation of a Supramolecular Network of Terarylene Molecules on Cu(111)

Bottom-up approaches allow for molecular-level control of engineering new nanostructures. For next-generation molecular circuits, machines, and phase-change materials, supramolecular structure formation and interactions must be investigated on a two-dimensional solid substrate. Scanning tunneling microscopy (STM) provides a method not only to address such supramolecular structures at the molecular level on a solid surface but also to locally control and manipulate such structures. In this article, we show that a terarylene molecule, a subfamily of photoswitching diarylethenes that promise a lot of applications from molecular switches to photoelectronics, assembles upon application of a bias voltage pulse from an STM tip. We show that molecules organize themselves in order to align their dipole moment to follow those of the electric field induced in the tunneling junction. The 2D assembly is stabilized by π–π stacking interactions and van der Waals interactions. This expands the repertoire of currently ava...