Narrow bandgap and enhanced electroconductivity in a dihydropyrene-thiophene copolymer

Incorporation of π electron-rich dihydropyrene units into the polymer backbone of polythiophene afforded a conducting polymer with narrow bandgap energy of about 1.0 eV. Doping of this polymer with iodine showed an optimum conductivity of about 1.0 S cm−1. The quinoid character and a small highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) separation in the dihydropyrene are believed to account for the observed semi-conducing properties of this dihydropyrene-thiophene copolymer. The dihydropyrene unit in the copolymer was found to exhibit a significantly higher thermal stability than the parent molecule.