Electrosynthesis and characterizations of electrochromic and soluble polymer films based on N- substituted carbazole derivates

Abstract

Carbazole derivatives are a class of nitrogen-containing aromatic heterocyclic compounds and they not only have various biological activities but also exhibit useful properties as organic materials due to their special structures. In this study, the compounds based on carbazole derivatives (N-positions were occupied by methanol, carboxylic acid, and cyanoethyl) were synthesized via a simple method. The electrochemistry and electropolymerization of these three monomers were investigated and compared with those of different N-substituted with groups attaching on the active sites of the carbazole units. The polymeric films were prepared on ITO/glass substrate by repetitive cyclic voltammetry (CV) scanning of the monomer solutions containing NaClO4-LiClO4 electrolyte dissolved in acetonitrile. The structures of the monomers and polymers were characterized by 1H-NMR, 13C-NMR, and FTIR. The electro-generated polycarbazole films exhibited redox-activity and multichromic properties with increasing potential. The remarkable electrochromic behavior of the films was explained in detail with the help of spectroelectrochemical studies. Photoluminescence spectra and quantum yields were given of polycarbazole samples in solution. In addition, solubility, molecular weight, and conductivity properties of polymers containing N-substituted groups have been discussed further.