Synthesis and Characterization of Poly(3-hexylthiophene)-b-Polystyrene for Photovoltaic Application

Poly(3-hexylthiophene)-block-polystyrene (P3HT-b-PS) was synthesized by Suzuki coupling reaction between P3HT and PS, prepared by Grignard metathesis polymerization and atom transfer radical polymerization (ATRP), respectively. The formation of block copolymer was confirmed by gel permeation chromatography (GPC) and NMR. Differential scanning calorimetry (DSC) thermogram of block copolymers showed glass transition of PS block and melting/crystallization of P3HT block, suggesting a microphase separated structure, which was also confirmed by atomic force microscopy (AFM) images and UV-vis absorption spectra. The annealing effect on the morphology of the composite films consisting of P3HT-b-PS and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was investigated. Photovoltaic cells fabricated using P3HT-b-PS and PCBM were evaluated