Effect of π-conjugation on electrochemical properties of poly(terthiophene)s 3′-substituted with fullerene C60

•The electrocopolymerization enabled the tuning of π-conjugation in 3′-C60-pyrrolidine-functionalised poly(terthiophene)s.•Different co-monomer ratio contributed to the distribution and cluster packing of C60 in the resulting polymer films.•The 3′-C60-pyrrolidine-functionalised poly(terthiophene)s can be used in photoelectrochemical devices.

The series of copolymers based on terthiophene 3′-substituted with C60-pyrrolidine or styryl group, were electrochemically synthesized and characterized. The dense distribution of C60 side group caused the steric effects between them and the perturbation in the extent of π–electron delocalization of the poly(terthiophene) backbone. The ESR spectroscopy showed the presence of close-packed clusters especially in homopolymer: poly(terthiophene-C60). The oxidative electrochemical copolymerization of terthiophene units was performed to avoid this steric interactions and in results to extend the effective π-conjugation length in the polymer. The use of different ratio of the co-monomers contributed to the variable distribution of C60 unit and different effective π-conjugation of the resulting polymers. Those changes affected electrochemical and photocurrent-generating properties of these materials.

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