On-Surface Synthesis and Characterization of Polythiophene Chains

Using the 5,5'-dibromo-2,2'-bithiophene (DBBT) precursor, we successfully fabricated high-quality polythiophene chains on Au(111) substrates via a versatile on-surface chemical synthetic route. The DBBT precursor self-assembly behaviors and the formed polythiophene chains have been characterized by scanning tunneling microscopy experiments and density functional theory calculations. The results show that the polythiophene chains can form a wide variety of conformational isomers, owing to the fact that each thiophene group rotates randomly around the sigma bond axis between two thiophene units. This work provides a new route toward constructing polythiophene and related substitutes on surfaces.