Site- and orientation-selective anchoring of a prototypical molecular building block.
The controlled anchoring of molecular building blocks on appropriate templates is a major prerequisite for the rational design and fabrication of supramolecular architectures on surfaces. We report on a particularly selective adsorption process of hexa-peri-hexabenzocoronene on Au(111), which leads to well-controlled adsorption position and orientation of the polycyclic aromatic hydrocarbons. Scanning tunneling microscopy reveals selective adsorption on monatomic steps in the fcc stacking regions with a specific orientation of 18 degrees between the molecular axis and the step normal. Ab initio calculations for various adsorption sites reveal the lowest total energy for adsorption on a kink site. Energy considerations and the excellent agreement between experimental and simulated images show that adsorption on kink sites is responsible for the specific adsorption angle.
Ruffieux
Pascal
P
Empa, Swiss Federal Laboratories for Materials Testing and Research, Feuerwerkerstrasse 39, 3602 Thun, Switzerland. pascal.ruffieux@empa.ch
Palotas
Krisztian
K
Gröning
Oliver
O
Wasserfallen
Daniel
D
Müllen
Klaus
K
Hofer
Werner A
WA
Gröning
Pierangelo
P
Fasel
Roman
R