Poly(2-decylthieno[3,4-b]thiophene). A new soluble low-bandgap conducting polymer

A new soluble low-bandgap conducting polymer, poly(2-decylthieno[3,4-b]thiophene) (5), has been prepared by a multistep synthetic sequence. The vis-NIR spectra of a film of 5 showed λmax = 738 nm with a band-edge bandgap of 1.2 eV. FeCl3 doping of the film gave a conductivity of 7.2 × 10−2 S cm−. The GPC molecular weight wasn = 30,000.