Conductive and Magnetic Properties of Poly(3,6-bis(2-(3,4-ethylenedioxy)thienyl)-N-dodecylcarbazole). A Polyconjugated Polymer with a High Spin Density Polaron State

Abstract

The polyconjugated bithiophene−carbazole regular copolymer poly(3,6-bis(2-(3,4-ethylenedioxy)thienyl)-N-dodecylcarbazole), produced by anodic coupling of the relevant monomer in acetonitrile and characterized by cyclic voltammetry, FTIR reflection−absorption, and UV−vis spectroscopy, has been investigated with electrochemical quartz crystal microbalance, in situ ESR and in situ conductivity techniques. The two isoelectronic oxidation processes produce the radical cation and dication forms of the polymer with charge localization at the bithiophene and carbazole subunits, respectively. Following the charge localization, the first oxidation produces a high spin density polymer with 0.25 spins per repeat unit. Furthermore two conductivity maxima (1 × 10-3 and 2.5 × 10-3 S cm-1) are shown in correspondence to the redox processes. A comparison is made with the in situ ESR and in situ conductivity results obtained from poly(N-ethylcarbazole).