Abstract

Photoactivities at inorganic/Organic/Interfaces (IOI) consisting of Zn-doped WO₃ (Zn-WO₃) /Poly 4-(Thiophen-3-yl) aniline (P3ThA) assemblies were investigated in nanoparticle suspensions and in thin solid film forms. The effects of P3ThA modifier on the photoelectrochemical behavior of the IOI were investigated using [Fe(CN)₆]^4- as a photoactive donor of hydrated electrons. Results show that the adsorption process of [Fe(CN)₆]^3- (photolysis product) controls the photoactivity outcomes of the IOI assemblies. P3ThA shows a greater heterogeneous photochemical response than native Zn-WO₃. The band alignment between Zn-WO₃ and P3ThA is of a p-p junction straddling gap type, where the charge transfer process is achieved through a hole transfer mechanism. The interface activities were explained by analyzing the IOI junction characteristics such as electron affinity, work function and hole/electron barrier heights. The creation of hybrid sub-band states close to the Fermi energy level at the interface was suggested. The aqueous nano-systems retained moderate stability as indicated by the reproducibility of their photocatalytic activities. Both [Fe(CN)₆]^4- and P3ThA contributed to the stability of the native Zn-WO₃ surfaces.

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