Modeling “Realistic” Self-Assembled Monolayers on Au(111)
Elisabeth Verwüster
Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
16:00 - 16:40 Friday 26 June 2015 HS 05.12 Physikgebaeude, Universitätsplatz 5

Covering a metal with a self-assembled monolayer (SAM) leads to a work-function modification of the underlying metal substrate. SAMs, especially on gold, offer a wide range of applications, such as corrosion protection, chemical-/biological sensors, or in organic electronics and opto electronics.1,2
Using SAMs in devices requires detailed understanding of the processes at the interface, which is the region where the molecules adsorb or covalently bind to the metal. This interface will in reality not be a perfectly ordered metal surface covered by a perfectly arranged densely packed monolayer. Thus its crucial to know what kind of defects can occur and what impact they have on desired observables.
A great amount of theoretical and experimental work has been done to investigate the properties of defected interfaces, but the topic still remains disputed in literature.3,4
To get more detailed insight into the binding-architecture and electronic properties of defected SAMs on Au(111), a set of prototypical SAMs including defects such as various surface reconstructions and modified coverages was modeled, using Density Functional Theory.
A significant impact of coverage and tail-group substitution (-CN, -CH3, -CF3, -NH2) on the investigated properties was found, whereas surface reconstructions mainly alter the docking-geometry and to a lesser part show an impact on electronic properties.


[1]Otsubo, T.; et al.; J. Mater. Chem. 2002, DOI: 10.1039/b203780g
[2]Kim, C.-H.; et al.; Adv. Mater. Interfaces 2014, DOI: 10.1002/admi.201400384
[3]Maksymovych, P.; et al.; J. Am. Chem. Soc. 2008, DOI: 10.1021/ja800577w
[4]Hannu Häkkinen; Nat.Chem. 2012, DOI: 10.1038/NCHEM.1352