Synthesis, polymerization and characterization of substituted dithieno[3,4-b:3′,4′-d]thiophenes

Chemical or electrochemical oxidation of substituted dithieno[3,4-b:3′,4′-d]thiophenes provides polymers with defined regiochemical structures. These materials have lower bandgaps (0.7-0.9 eV) than the unsubstituted fused heteroarene. Potential cycling of the 1,3-dimethyl substituted polymer film shows repetitive p- and n-dopability. The chemically-prepared dioctyl analog is soluble in common solvents such as chloroform, dichloromethane and THF. However, overoxidation of the polymers at an electrode surface presents a limitation to the polymerization of substituted analogs of the parent fused heteroarene.