Influence of the electrochemical conditions on the properties of polymerized carbazole

Polycarbazole (PCZ) was obtained by electrochemical oxidation of carbazole monomers. Two potentials were used: the oxidation potential of the monomer 1700 mV and an over oxidation potential 2500 mV. The carbazole monomers were supplied either in solution in the electrolyte or in the form of pre-deposited thin film evaporated on a working electrode. It is shown that if PCZ is systematically obtained its electrical and morphological properties are strongly dependent on the experimental conditions. The stability of over-oxidized PCZ films corresponds to chain reticulation beyond the first oxidation potential value, with the loss of flexibility of the chains and steric hindrance, which decreases the carrier mobility and, therefore, its conductivity. The polymers obtained at the oxidation of carbazole have conductivity corresponding to higher carrier mobility. These polymers are conjugated. Moreover, in the case of preevaporated carbazole thin film the coverage of the SnO2 is very high and the films are homogenous.