title: Structural investigation of 1,1'-biphenyl-4-thiol self-assembled monolayers on Au(111) by scanning tunneling microscopy and low-energy electron diffraction.
abstract: Self-assembled monolayers (SAMs) of 1,1'-biphenyl-4-thiol (H-(C(6)H(4))(2)-SH) on Au(111) were prepared from solution or via vapor deposition in ultrahigh vacuum and characterized by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and X-ray photoelectron spectroscopy (XPS). In contrast to the typically observed for densely packed alkane-thiol SAMs on Au(111) (√3 × √3)R30° structure, the densely packed aromatic biphenylthiol SAMs prepared by both methods exhibit an unusual hexagonal (2 × 2) structure. Upon annealing at 100 °C, this structure evolves into the (2 × 7√3) structure resulting in the formation of highly ordered pinstripes oriented along the [1 -1 0] directions. Lower density SAMs, prepared by vapor deposition in vacuum, show mixed structures comprising the hexagonal (2 × 2) structure and two rectangular arrangements with the unit cells of (3√3 × 9) and (2√3 × 8). An extinction of the (3√3 × 9) structure in the favor of the (2√3 × 8) structure is observed upon annealing at temperatures of ~100 °C.
authors.affiliation: Physics of Supramolecular Systems and Surfaces, University of Bielefeld, Bielefeld, Germany.
authors.forename: D G
authors.initials: DG
authors.lastname: Matei
authors.forename: H
authors.initials: H
authors.lastname: Muzik
authors.forename: A
authors.initials: A
authors.lastname: Gölzhäuser
authors.forename: A
authors.initials: A
authors.lastname: Turchanin
mesh_terms: D001713:Biphenyl Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D004583:Electrons; D006046:Gold / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D015394:Molecular Structure; D013053:Spectrophotometry; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D014965:X-Rays
chemical_list: C578315:1,1'-biphenyl-4-thiol; D001713:Biphenyl Compounds; D013438:Sulfhydryl Compounds; D006046:Gold