The interaction of aluminum and p-sexiphenyl

Aluminum is widely used as cathode material in organic electroactive devices. In this work the interface formation between the electroluminescent material p-sexiphenyl (6P) and this metal was investigated with photoelectron spectroscopy. In strong contrast to the findings for the interaction of polyenes and oligothiophenes with Al, where covalent bonds are formed, we obtain clear evidence for physisorption of Al on 6P. This is supported by quantum chemical calculations, carried out on model systems.