Unique optical and electrochemical properties of π-conjugated electrically conducting copolymers consisting of electron-withdrawing pyridine units and electron-donating thiophene units

Electrically conducting π-conjugated copolymers consisting of π-excessive thiophene-2,5-diyl and π-deficient pyridine-2,5-diyl monomer units show a unique cyclic voltammogram with an unusually large potential difference between the doping and the undoping peaks, and their electronic and fluorescence spectra support occurrence of intramolecular charge transfer showing absorption and fluorescence peaks at lower energy compared with those of the corresponding homopolymers.