Synthesis and Electropolymerization of 9-tosyl-9H-carbazole, Electrochemical Impedance Spectroscopic Study and Circuit Modelling

This work reports on the newly synthesized 9-tosyl-9H-carbazole (TsCz) monomer. Capacitive properties of the electrochemically grown homopolymer, poly(TsCz) film on carbon fibre microelectrode (CFME), are characterised by cyclic voltammetry (CV), Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Different monomer concentrations (1, 3 and 10 mM) were used for electrodeposition in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The capacitive behaviour of modified CFMEs was defined via Nyquist, Bode-magnitude and Bode-phase plots. An equivalent electrical circuit R(CR)(QR)(CR) for different concentrations of poly(TsCz)/CFME was proposed and experimental data were simulated to obtain the numerical values of the circuit components. The Nyquist plot for poly(TsCz) shows the highest specific capacitance (50.0 mF cm(-2)) at frequency of 0.01 Hz in the initial monomer concentration of 10 mM.