Electron-Rich Thienylene−Vinylene Low Bandgap Polymers

A series of alternating copolymers of 2,5-(3,4-ethylenedioxy)thiophene and 1,2-vinylene with well defined repeat unit ratios were synthesized and characterized electrochemically and spectroscopically. By increasing the vinylene to thiophene ratio from 0:1 to 0.5:1 to 1:1 along the polymer backbone, the bandgap of the resulting polymers were reduced systematically as clearly evidenced by absorption spectroscopy. The 1:1 copolymer exhibited an onset bandgap of 1.0 eV.