Long-Range Ordered Structures of Corannulene Governed by Electrostatic Repulsion and Surface-State Mediation

Area of Science:

• Surface Science
• Materials Chemistry
• Nanotechnology

Background:

• Corannulene (COR) is a bowl-shaped polycyclic aromatic hydrocarbon with unique electronic properties.
• Understanding molecular adsorption and assembly on metal surfaces is crucial for designing novel functional materials.
• Copper (Cu(111)) and Silver (Ag(111)) are model substrates for studying surface phenomena.

Purpose of the Study:

• To investigate the adsorption and self-assembly of corannulene on Cu(111) and Ag(111) surfaces.
• To elucidate the intermolecular interactions governing corannulene assembly at different coverages.
• To characterize the different molecular configurations and emergent patterns.

Main Methods:

• Scanning Tunneling Microscopy (STM) was employed for high-resolution imaging of molecular adsorption and assembly.
• Quantitative analysis was performed to evaluate intermolecular interactions.
• Varying sub-monolayer coverages of corannulene were studied.

Main Results:

• Three distinct corannulene configurations (up, down, tilted) were observed on Cu(111).
• Monodispersed, hexagonal, and stripe patterns were formed on both Cu(111) and Ag(111).
• At low coverage (0.05 ML), electrostatic repulsion dominates pattern formation.
• At higher coverages (0.24 and 0.47 ML), surface-state mediation becomes the primary driving force for assembly.

Conclusions:

• Corannulene exhibits rich self-assembly behavior on metal surfaces, influenced by substrate and coverage.
• The transition from electrostatic repulsion to surface-state mediation dictates the observed patterns.
• This study provides insights into controlling molecular assembly for potential applications in nanotechnology.