Tuning the electronic structure of conjugated polymers with fluoroalkyl substitution: Alternating alkyl/perfluoroalkyl-substituted polythiophene

The electronic properties of the conjugated backbone of polythiophene can be tailored by the incorporation of alkyl and perfluoroalkyl substituents. A regioregular copolymer with alternating alkyl and perfluoroalkyl. substituents displays absorption and emission maxima between those of the homopolymers composed of the individual structural units. However, the combination of the alternating electron-rich and electron-poor units, together with a small twisting influence of the perfluoroalkyl groups, provides a material which displays enhanced solution-phase fluorescence and strong solid-state fluorescence which is absent for the wholly alkyl analogue.