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 wer e supplied either in solution in the electrolyte or in the form of pre-depo sited 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-ox idized PCZ films corresponds to chain reticulation beyond the first oxidati on potential value, with the loss of flexibility of the chains and steric h indrance, which decreases the carrier mobility and, therefore, its conducti vity. The polymers obtained at the oxidation of carbazole have conductivity corresponding to higher carrier mobility. These polymers are conjugated. M oreover, in the case of preevaporated carbazole thin film the coverage of t he SnO2 is very high and the films are homogenous. (C) 2001 Kluwer Academic Publishers.