title: Anomalous coarsening driven by reversible charge transfer at metal-organic interfaces.
abstract: The unique electronic properties and functional tunability of polycyclic aromatic hydrocarbons have recently fostered high hopes for their use in flexible, green, portable, and cheap technologies. Most applications require the deposition of thin molecular films onto conductive electrodes. The growth of the first few molecular layers represents a crucial step in the device fabrication since it determines the structure of the molecular film and the energy level alignment of the metal-organic interface. Here, we explore the formation of this interface by analyzing the interplay between reversible molecule-substrate charge transfer, yielding intermolecular repulsion, and van der Waals attractions in driving the molecular assembly. Using a series of ad hoc designed molecules to balance the two effects, we combine scanning tunnelling microscopy with atomistic simulations to study the self-assembly behavior. Our systematic analysis identifies a growth mode characterized by anomalous coarsening that we anticipate to occur in a wide class of metal-organic interfaces and which should thus be considered as integral part of the self-assembly process when depositing a molecule on a conducting surface.
authors.affiliation: Department of Chemistry, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Ada
authors.initials: A
authors.lastname: Della Pia
authors.forename: Massimo
authors.initials: M
authors.lastname: Riello
authors.forename: Andrea
authors.initials: A
authors.lastname: Floris
authors.forename: Daphne
authors.initials: D
authors.lastname: Stassen
authors.forename: Tim S
authors.initials: TS
authors.lastname: Jones
authors.forename: Davide
authors.initials: D
authors.lastname: Bonifazi
authors.forename: Alessandro
authors.initials: A
authors.lastname: De Vita
authors.forename: Giovanni
authors.initials: G
authors.lastname: Costantini
keywords: charge transfer; interfacial dipoles; metal−organic interfaces; polycyclic aromatic hydrocarbons; self-assembly at surfaces