Energy-level alignment and charge injection at metal/C60/organic interfaces

The energy-level alignment and charge injection at metal/C60/organic interfaces have been studied by ultraviolet photoelectron spectroscopy and temperature dependent current-voltage (IV) measurements. It is found that the Fermi level at the interface is pinned to ∼4.7eV by adsorbed C60 molecules on the metal surface, resulting in more favorable energy level alignment for charge injection. The findings are in excellent agreement with interface dipole theory derived from traditional semiconductor physics.