A photoelectron emission study of conducting polymer/metal interfaces

Ionization potentials of metal/conducting polymer interfaces and conducting polymer/poly(p-pyridyl vinylene), PPyV, interfaces have been evaluated by low-energy photoelectron spectroscopic method and nano-interfacial electronic states were determined. At all the measured interfaces, shift of the vacuum level was observed, showing the formation of an interfacial electric dipolar layer. The shifts of the ionization potential at the interface could be expressed as a linear function of work function of the contact metal. But, for conducting polymers/ ITO, interfaces, nano-interfacial electronic states could not be determined, because of observed novel ionization potential behavior in these systems. The present results have clearly demonstrated that sufficient clarification of the interfacial electronic states is necessary for understanding the properties of the organic electronic devices.