Self-Assemblies and Properties of Side-On Picene Strips on a Monolayered CuO Film

Thermally deposited picene (C22H14) molecules on a monolayered CuO film were grown at a Cu(110) self-assemble into side-on molecular strips extending along the [1 (1) over bar0] direction, as revealed by scanning tunneling microscopy (STM). The picene molecules are closely stacked on and anchored to the Cu-O chains via their armchair edges. They form two stacking modes and stick to the substrate via their long (Pic-I) and short (Pic-II) armchair edges. Such configurations are reversibly switchable by either an applied STM bias voltage pulse or continuous tip navigation. Scanning tunneling spectroscopies acquired above the Pic-I and Pic-II strips reveal different electronic states, showing a clear relationship between their electronic structures and their stacking modes on the substrate.