Very Stable Low Band Gap Polymer for Charge Storage Purposes and Near-Infrared Applications

A new low band gap polymer, poly(1,3-bis(2‘-[3‘,4‘-ethylenedioxy]thienyl)-benzo[ c ]thiophene- N -2‘ ‘-ethylhexyl-4,5-dicarboximide) P(DEDOT-ITNIm), was synthesized. Electrochemically prepared polymer films were very stable to overoxidation upon p-doping and stable upon n-doping. The low band gap of the polymer films, 1.10 eV, was determined from electrochemistry and spectroelectrochemistry. Thin polymer films on ITO-coated glass slides showed exceptional optical properties upon both p- and n-doping, these were small changes in the transparency and color of the polymer in the visible region but more dramatic changes in the near-infrared region. The charge storage capacity of P(DEDOT-ITNIm) films is very high when compared to other members of the conducting polymers family, making this polymer a good candidate for charge storage purposes; e.g., as supercapacitors.