  We investigate charge transport in pentacene-graphene nanojunctions employing
density functional theory (DFT) electronic structure calculations and the
Landauer transport formalism. The results show that the unique electronic
properties of graphene strongly influence the transport in the nanojunctions.
In particular, edge states in graphene electrodes with zigzag termination
result in additional transport channels close to the Fermi energy which deeply
affects the conductance at small bias voltages. Investigating different linker
groups as well as chemical substitution, we demonstrate how the transport
properties are furthermore influenced by the molecule-lead coupling and the
energy level lineup.
