Engineering high charge transfer n-doping of graphene electrodes and its application to organic electronics

Using thermally evaporated cesium carbonate (Cs2CO3) in an organic matrix, we present a novel strategy for efficient n-doping of monolayer graphene and a similar to 90% reduction in its sheet resistance to similar to 250 Ohm sq(-1). Photoemission spectroscopy confirms the presence of a large interface dipole of similar to 0.9 eV between graphene and the Cs2CO3/organic matrix. This leads to a strong charge transfer based doping of graphene with a Fermi level shift of similar to 1.0 eV. Using this approach we demonstrate efficient, standard industrial manufacturing process compatible graphene-based inverted organic light emitting diodes on glass and flexible substrates with efficiencies comparable to those of state-of-the-art ITO based devices.