A regioregular polythiophene-fullerene for polymeric solar cells

In this article, we present the synthesis and characterization of a new thiophenic copolymer bearing the C 60 fullerene directly linked to the end of a hexamethylenic side chain. This copolymer was prepared with good yield using a simple and straight- forward post-polymerization functionalization procedure applied on a soluble regioregular polymeric precursor obtained by regiospe- cific organometallic coupling. Copolymer structural and photophysical properties were investigated by gel permeation chromatography, thermal analysis (DSC and TGA), NMR, IR, UV–Vis, and atomic force spectroscopy. The double-cable copolymer possesses good solubility in common organic solvents, high filmability, thermal stability, and low segmental aggregation tendency. It was tested as a photoactive layer in a polymeric solar cell showing a power conversion efficiency under 100 mW cm 22 AM 1.5 illumi- nation higher than 4%, more than that of the reference cell made with the conventionally used P3HT/PCBM blend.