(Invited) Self-Assembly on Graphene and 2D Materials

Abstract

Nanostructured monolayers of molecules can be formed at a variety of interfaces. At a liquid-solid interface, such two-dimensional (2D) molecular assemblies can be created by depositing a solution of the compound of interest on top of the substrate (drop casting) or by immersing the substrate into a solution (dip coating). Very often, only weak non-covalent interactions govern the interplay between molecules and molecules and substrate. Advanced interface specific methods such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM) provide structural and other types of information at the nanoscopic level. In this presentation, we focus on several aspects of molecular self-assembly at the interface between a liquid or air, and substrates such as highly oriented pyrolytic graphite and graphene. Highly oriented pyrolytic graphite can be considered as an excellent model surface for adsorption and self-assembly of molecules on graphene. We will discuss the concept of 2D crystal engineering and the effect of solvent, solute concentration and temperature, bringing insight into thermodynamic and kinetics aspects of the self-assembly process at the interface between a liquid and graphite or graphene.1,2 Based on these insights, we will demonstrate molecular self-assembly based functionalization of graphite and graphene.3 Various applications will be presented,4 including tunable doping of graphene based field effect transistors5. (1) De Feyter, S.; De Schryver, F. C. Chem.Soc.Rev. 2003, 32, 139. (2) Mali, K. S.; Adisoejoso, J.; Ghijsens, E.; De Cat, I.; De Feyter, S. Acc.Chem.Res. 2012, 45, 1309. (3) Li, B.; Tahara, K.; Adisoejoso, J.; Vanderlinden, W.; Mali, K. S.; De Gendt, S.; Tobe, Y.; De Feyter, S. ACS Nano 2014, 7, 10764. (4) Xu, H.; Saletra, W. J.; Iavicoli, P.; Van Averbeke, B.; Schenning, A. P. H. J.; Beljonne, D.; Lazzaroni, R.; Amabilino, D. B.; De Feyter, S. Angew. Chem. Int. Ed. 2012, 51, 11981. (5) Li, B.; Klekachev, A.; Cantoro, M.; Huyghebaert, C.; Stesmans, A.; Asselberghs, I.; De Gendt, S.; De Feyter, S. Nanoscale 2013, 5, 9640. Figure 1