Structure and Energetics of Shuttlecock-Shaped Tin-Phthalocyanine on Ag(111): A Density Functional Study Employing Dispersion Correction
Journal article, 2012

The reversible switch between two electronically and/or geometrically distinct states of a single molecule adsorbed on a well-characterized substrate is of high technological interest due to its possible use as single molecule devices and novel molecular memories. We have studied shuttlecock-shaped metal phthalocyanines, which can adsorb on surfaces in two distinct adsorption configurations, depending on if the central metal atom points toward or away from the surface, and we report on the adsorption of tin-phthalocyanine (SnPc) on an Ag(111) surface using density functional theory (DFT) including a semiempirical dispersion correction (DFT-D).We discuss the binding mechanism in detail and show that the adsorption of SnPc in these two orientations is driven by very different interactions. While "Sn-down" adsorption involves chemical bonding between Sn and the surface (chemisorption), the "Sn-up" configuration is bound only by weak van der Waals forces (physisorption). By comparing our theoretical results with a broad range of experimental data, we assess the effect of dispersion forces for the SnPc/Ag(111) system and how these impact adsorption energies, geometries, and the electronic structure. We show that an inclusion of dispersion forces improves the adsorption geometry with respect to experiment and is essential in order to capture the subtle electronic effects at molecule metal interfaces. By analyzing the geometric and electronic structure of the adsorbed molecules we, in addition, shed light on the surprising 2-fold symmetry reduction of metal phthalocyanine molecules that has been observed upon adsorption on surfaces.

pseudopotentials

augmented-wave

elements

organic films

metals

basis-set

method

transition

total-energy calculations

initio molecular-dynamics

electronic-structure

Author

Jakub Baran

Competence Centre for Catalysis (KCK)

Chalmers, Applied Physics, Chemical Physics

J. A. Larsson

Tyndall National Institute at National University of Ireland, Cork

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 116 17 9487-9497

Subject Categories

Chemical Sciences

DOI

10.1021/jp210771d

More information

Created

10/7/2017