The effect of chain microstructure on electrochemical and spectroelectrochemical properties of fluorenone–dialkyl bithiophene alternate copolymers

• Published in: Electrochimica acta 2005-02, Vol.50 (7), p.1597-1603
• Main Authors: Demadrille, Renaud, Divisia-Blohorn, Bernadette, Zagorska, Malgorzata, Quillard, Sophie, Lefrant, Serge, Pron, Adam
• Format: Article
• Language: English
• Subjects: Alkylthiophene–fluorenone alternate copolymers; Analytical chemistry; Chemical Sciences; Cyclic voltammetry; Material chemistry; Organic chemistry; Polymers; UV–vis-NIR and Raman spectroelectroelectrochemistry
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2004.10.039

Voltammetric and spectroelectrochemical behavior of two newly synthesized conjugated polymers, which show the same chemical constitution but different type of regioregularity, is compared. These are poly(fluorenone- alt-dioctyl bithiophene)s in which the alkylthiophene rings are either head to head (HH) or tail to tail (TT) coupled, termed PFDOBT-HH and PFDOBT-TT, respectively. Both polymers can be electrochemically p- and n-doped and show the electrochemical energy gap ( E g el ) of the order of 2 eV. In the oxidation side of the voltammogram PFDOBT-HH gives a relatively narrow anodic peak with a maximum at E = 0.78 V versus Fc/Fc +. The corresponding peak of PFDOBT-TT is much broader with the maximum shifted to slightly lower potentials ( E = 0.74 V versus Fc/Fc +). UV–vis-NIR and Raman spectroelectrochemical studies confirm that the oxidative doping of PFDOBT-TT starts at lower potentials and indicate significant differences in the anodic oxidation in both cases. In PFDOBT-HH the doping is sequential, which means that it starts by the oxidation of the bithiophene sub-units and is completed by the oxidation of the fluorenone ones. In the case of PFDOBT-TT both sub-units are doped simultaneously.