AVS 45th International Symposium
    Organic Electronic Materials Topical Conference Monday Sessions
       Session OE-MoP

Paper OE-MoP6
Structures and Growth of Monolayers of 4-methyl-4’-mercaptobiphenyl on Au(111): The Role of the Molecular Backbone

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Organic Electronic Materials Poster Session
Presenter: T.Y.B. Leung, Princeton University
Authors: T.Y.B. Leung, Princeton University
P. Eisenberger, Columbia Earth Institute
F. Schreiber, Max-Planck-Institut für Metallforschung, Germany
P. Schwartz, Princeton University
A. Ulman, Polytechnic University
G. Scoles, Princeton University
Correspondent: Click to Email
We present the results of a comprehensive diffraction study of monolayers of 4-methyl-4’-mercaptobiphenyl assembled on Au(111) [abbreviated as mbp]. Two phases of different density are observed. The diffraction patterns suggest that a low-density phase can be comprised of molecules assembling in rows with their molecular axes parallel to the surface. A second, high-density phase is thought to be composed of a hexagonal arrangement of molecules, which are aligned along the surface normal. We denote the low-density phase as the "striped" phase and the high-density phase as the "hexagonal" phase. Although the striped phase and the hexagonal phase are also observed in monolayers of n-alkanethiol on Au(111) [abbreviated Cn], interesting differences have been found. Apart from the structural differences, annealing experiments show that both phases of mbp are more thermally stable than the phases of Cn. In addition, the growth behaviour of mbp is investigated and different growth protocols have been attempted. Unlike the case of Cn where the hexagonal phase can be grown reliably and reproducibly, the hexagonal phase of mbp has only been observed a few times. We will address the role of the molecular backbone in the self-assembly process process of thiol on gold, based on the disparities in the structures, the thermal behaviour, and the growth behaviour between mbp and Cn.