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

• Two triphenylamine- and carbazole-based monomers were synthesized and characterized.
• New conjugated polycarbazoles were prepared by electrochemical polymerization.
• Optical and electrochemical properties of the polymer films were investigated.
• The polymer films show p-type doping and anodically coloring properties.

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.

Figure optionsDownload as PowerPoint slide