jz6b00223_si_001.pdf (1.1 MB)
Identical Binding Energies and Work Functions for Distinct Adsorption Structures: Olympicenes on the Cu(111) Surface
journal contribution
posted on 2016-02-29, 00:00 authored by Wei Liu, Bruno Schuler, Yong Xu, Nikolaj Moll, Gerhard Meyer, Leo Gross, Alexandre TkatchenkoReliability is one of the major concerns
and challenges in designing
organic/inorganic interfaces for (opto)electronic applications. Even
small structural differences for molecules on substrates can result
in a significant variation in the interface functionality, due to
the strong correlation between geometry, stability, and electronic
structure. Here, we employed state-of-the-art first-principles calculations
with van der Waals interactions, in combination with atomic force
microscopy experiments, to explore the interaction mechanism for three
structurally related olympicene molecules adsorbed on the Cu(111)
surface. The substitution of a single atom in the olympicene molecule
switches the nature of adsorption from predominantly physisorptive
character [olympicene on Cu(111)], to an intermediate state [olympicene-derived
ketone on Cu(111)], then to chemisorptive character [olympicene radical
on Cu(111)]. Despite the remarkable difference in adsorption structures
(by up to 0.9 Å in adsorption height) and different nature of
bonding, the olympicene, its ketone, and its radical derivatives have
essentially identical binding energies and work functions upon interaction
with the metal substrate. Our findings suggest that the stability
and work functions of molecular adsorbates could be rendered insensitive
to their adsorption structures, which could be a useful property for
(opto)electronic applications.