Publication Type : Journal Article
Publisher : Nanoscale
Source : Nanoscale, Volume 10, p.8014-8022 (2018)
Url : https://pubs.rsc.org/en/content/articlelanding/2018/nr/c7nr08737c#!divAbstract
Campus : Bengaluru
School : School of Engineering
Department : Electronics and Communication
Year : 2018
Abstract : We compare the ultrafast charge transfer dynamics of molecules on epitaxial graphene and bilayer graphene grown on Ni(111) interfaces through first principles calculations and X-ray resonant photoemission spectroscopy. We use 4,4′-bipyridine as a prototypical molecule for these explorations as the energy level alignment of core-excited molecular orbitals allows ultrafast injection of electrons from a substrate to a molecule on a femtosecond timescale. We show that the ultrafast injection of electrons from the substrate to the molecule is ∼4 times slower on weakly coupled bilayer graphene than on epitaxial graphene. Through our experiments and calculations, we can attribute this to a difference in the density of states close to the Fermi level between graphene and bilayer graphene. We therefore show how graphene coupling with the substrate influences charge transfer dynamics between organic molecules and graphene interfaces.
Cite this Research Publication : Abhilash Ravikumar, Kladnik, G., Müller, M., Cossaro, A., Bavdek, G., Patera, L. L., Sánchez-Portal, D., Venkataraman, L., Morgante, A., Brivio, G. Paolo, Cvetko, D., and Fratesi, G., “Tuning Ultrafast Electron Injection Dynamics at Organic-Graphene/Metal Interfaces”, Nanoscale, vol. 10, pp. 8014-8022, 2018.