Electrochemical synthesis and electrochromic properties of new conjugated polycarbazoles from di(carbazol-9-yl)-substituted triphenylamine and N-phenylcarbazole derivatives

Two carbazole end-capped monomers containing triphenylamine or N-phenylcarbazole as an interior core, namely 4,4'-di(carbazol-9-yl)-4 ''-methoxytriphenylamine (TPA-2Cz) and 3,6-di(carbazol-9-yl)-N-(4-methoxyphenyl)carbazole (PhCz-2Cz), were prepared by a well-known chemistry from readily available reagents. The electrochemistry and electropolymerization of these two monomers were investigated and compared with those of structurally similar analogs with tert-butyl groups attaching on the active sites of the end-capped carbazole units. The polymeric films were built onto ITO/glass surface by repetitive cyclic voltammetry (CV) scanning of the monomer solutions containing an electrolyte. The electro-generated polycarbazole films exhibited high redox-activity and strong color changes upon electro-oxidation, which can be switched by potential modulation. The remarkable electrochromic behavior of the film was clearly interpreted on the basis of spectroelectrochemical studies, and the electrochromic stability was evaluated by the electrochromic switching studies. (C) 2015 Elsevier B.V. All tights reserved.