Photoelectrochemical and magnetic studies on photoactive interface thin film assemblies of poly bithiophene/poly 3-(2-thienyl) aniline/ferromagnetic Mg-doped Fe2O3 in aqueous electrolytes

Abstract

Organic/organic/inorganic interface or (OOI) thin film assemblies were created from poly 2,2 bithiophene and poly 3-(2-thienyl) aniline (PThA) and Mg-doped Fe2O3. Surface modification of Fe2O3 nanoparticles with PThA was achieved using photopolymerization of 3-(2-thienyl) aniline. Particles of PThA/Fe2O3 were occluded during the electropolymerization process of 2,2 bithiophene on a fluorine doped tin oxide glass electrode. The OOI assemblies were subjected to photoelectrochemical investigation in aqueous electrolytes containing acetate, citrate, tartrate, and phosphate. As all components of the assembly are p-type semiconductors, the produced interface are of a p-p junction nature. Our results show that the behavior of the assemblies reflects formation of hybrid sub-bands as a product of band alignments between the organic film and Fe2O3. Furthermore, O2 played an important role in the charge separation and transfer processes. The assembly responses to an applied magnetic field was investigated and reported. The results were explained on the basis that external magnetic fields affect the photogeneration of singlet/triplet radical pair processes. The present studies also show that the longest electron life-time was recorded in citrate buffer.