Synthesis and characterization of novel fluorene–thiophene-based conjugated copolymers

A novel series of soluble alternating conjugated copolymers comprised of 9,9-dihexylfluorene and substituted bithiophene or thiophene moieties have been synthesized by palladium-catalyzed Suzuki coupling reaction. The polymer structures were characterized and confirmed by NMR, FT-IR, and elemental analysis. The defined structures of the polymers provide us the possibility to study the structure–property relationships of the polymers based on the hybrid backbones, especially by controlling the substitution on thiophene rings and the coupling configurations between two adjacent thiophene rings. All of the four polymers have demonstrated efficient blue-to-green light emission, good solubility in common organic solvents, good thermal stability, relatively high glass transition temperatures and good electrochemical properties.