Electrochemical impedance spectroscopy characterization of conducting polymer/TiO2 nanotube array hybrid structures

• Hybrid structures are made of conducting polymers on nanostructured titanium oxide.
• Impedance measurements are performed on hybrid structures.
• A model from the literature is adapted to the hybrid structures.
• Modification of the semiconducting behavior is observed in the presence of polymers.

The model suggested by Deslouis and co-workers [14] for describing the behavior of polypyrrole deposited on a metallic substrate is here used for conducting polymers deposited on a nanostructured 3D semiconducting substrate. Impedance measurements were performed on a titanium oxide nanotubular array in the presence of two types of conducting polymers: polypyrrole and poly(3,4-ethylenedioxythiophene), highlighting the modification of the semiconducting properties of the substrate induced by the polymer deposition. The model is shown to be particularly well adapted for the PEDOT/TiO2 hybrid structure, providing a valuable tool for characterizing the interaction between the conducting polymer and the semiconducting substrate.