Molecular Tunnel Junctions Based on π-Conjugated Oligoacene Thiols and Dithiols between Ag, Au, and Pt Contacts: Effect of Surface Linking Group and Metal Work Function

Understanding the role of metal–molecule contacts in molecular electronics experiments remains a major challenge.(1-12) In a typical molecular junction, a molecule or an ensemble of molecules is contacted at either end by metal electrodes, Figure 1. The goal is to understand the current–voltage (I–V) characteristics in terms of the molecular structure and the type of chemical linking groups (X) employed to connect the molecules to the electrodes. However, in these two-terminal measurements one does not have independent knowledge of the potential profile across the junction, and thus the relative contribution of the contacts to the junction I–V characteristic (or total resistance) is generally unknown.