Synthesis and characterization of carboxystyryl end-functionalized poly(3-hexylthiophene)/TiO2 hybrids in view of photovoltaic applications

The modification of TiO2 nanoparticles by a carboxystyryl end-group functionalized poly(3-hexylthiophene) has been reported leading to improved dispersion stability and increased photo-induced electron transfer efficiency. [Display omitted] ► TiO2 NPs were functionalized by a carboxystyryl end-group functionalized P3HT. ► P3HT/TiO2 hybrid materials exhibit improved dispersion stability. ► An increased photo-induced electron transfer efficiency is observed in the hybrid material. Regioregular head-to-tail α-bromo-ω-carboxystyryl poly(3-hexylthiophene) (P3HT-COOH) has been prepared by a Wittig reaction of α-bromo-ω-formyl poly(3-hexylthiophene) (P3HT-CHO) with [(4-carboxyphenyl)methyl]triphenylphosphonium bromide. This carboxylic end-group functionalized polymer was used to functionalize TiO2 nanoparticles in view of improving the miscibility between poly(3-hexylthiophene) and the nanoparticles, for future photovoltaic applications. The anchoring of the polymer on the surface of the TiO2 nanoparticles was demonstrated by sedimentation tests in THF, and by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), 1H MAS solid-state NMR, UV–vis and X-ray photoelectron spectroscopies. Films were produced by solvent casting and the dispersion of the TiO2 nanoparticles was evaluated by atomic force microscopy (AFM). Fluorescence quenching studies in CHCl3 were performed on these hybrids materials.