Photoelectrochemical Studies on High Specific Capacitance-Photoactive Interfaces Based on Poly 3,4- Ethylenedioxythiophene/Metal Oxides Assemblies

Abstract

Inorganic/organic interfaces (IOI) consist of TiO 2 /PEDOT (poly 3,4-ethylenedioxythiophene) and [PMo 12 O 40 ] 3- or MoO 3 /PEDOT were subject to photoelectrochemical studies in both aqueous nanosuspensions and in thin solid films. The effects PEDOT modifier caused on the photoelectrochemical behavior of the IOI were investigated using [Fe(CN) 6 ] 4- as the photoactive hydrated electron donor agent. Results show that native PEDOT or PEDOT doped with MoO 3 thin films increased charge storage capability evident by the high capacitive current. In the case of nano suspensions composed of TiO 2 /PEDOT the adsorption process of [Fe(CN) 6 ] 3- (photolysis product) control of the photoactivity outcome of the IOI assemblies. TiO 2 /PEDOT shows a lower heterogeneous photochemical response than native TiO 2 in short term photolysis times. At longer photolysis times the IOI shows photoactivity greater than that of native TiO 2 . The interface activities were explained by analyzing the IOI junction characteristics, such as electron affinity, work function and hole/electrons barrier heights. The aqueous nano-systems retained moderate stability as indicated by the reproducibility of their photocatalytic activities. Both [Fe(CN) 6 ] 4- and PEDT contributed to the stability of native TiO 2 surfaces.