Bithiophene-Perfluorobenzene Copolymers

A series of copolymers of 3,3 '-dialkylbithiophenes and tetrafluorobenzene units are reported along with non-fluorinated controls. All are characterized by NMR, gel permeation chromatography, differential scanning calorimetry, optical spectroscopy, and wide-angle X-ray diffraction (WAXD). The fluorine substituents enhance backbone planarity, order, and pi-stacking in the solid-state as revealed by optical spectroscopy and WAXD. Peak oxidation potential is also increased by 0.55 V relative to a benchmark polymeric semiconductor, poly(3-hexylthiophene). Head-to-head 3-alkylthiophene linkages do not preclude backbone planarity provided the side chains are not too bulky.