A joint experimental and theoretical study of the interaction between aluminum and electroluminescent polymers: Cyano derivatives of poly(p-phenylene vinylene)

The early stages of metal/polymer interface formation between aluminum and poly(2,5,2',5'-tetrahexyloxy-8,7'-dicyanodi-p-phenylenevinylene) or their ring-substituted derivatives have been studied theoretically by using quantum-chemical calculations as well as experimentally by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. This class of conjugated polymer is of interest in the development of organic light-emitting diodes. The theoretical and experimental results indicate that aluminum preferentially reacts with the polymer by forming covalent bonds with the nitrogen and carbon atoms of the cyano groups. When the side chains of the phenylene rings include carbonyl groups, however, the theoretical results indicate that the carbonyl moiety is another preferred site of interaction.