Poly(3,5-dithiophene-2-yldithieno[3,2-b;2′,3′-d]thiophene-co-Ethylenedioxythiophene)/Glassy Carbon Electrode Formation and Electrochemical Impedance Spectroscopic Study

Abstract

3,5-Dithiophene-2-yldithieno[3,2-b;2′,3′-d]thiophene (Thy 2DTT) and ethylenedioxythiophene (EDOT) were electro-copolymerized on glassy carbon electrode (GCE) in 0.1 M sodium perchlorate (NaClO 4+δ)acetonitrile (ACN)dichloromethane (CH 2Cl 2) (8:2) solution. Poly(Thy 2DTT-co-EDOT)GCE thin film was characterized by various techniques, such as Cyclic Voltammetry (CV), Fourier Transform Infrared Spectroscopy - Attenuated Transmittance Reflectance (FTIR-ATR), Scanning Electron Microscopy - Energy Dispersive X-ray analysis (SEM-EDX) and Electrochemical Impedance Spectroscopy (EIS). The effects of monomer mole fractions (mole fraction, X Thy2DTT=n Thy2DTTn EDOT+n Thy2DTT) (0.5, 0.66 and 0.83) during the preparation of modified electrodes were examined by EIS. Capacitive behaviors of the modified GCE were defined via Nyquist, Bode-magnitude, Bode-phase and Capacitance plots. The circuit model was used to fit the theoretical and experimental data through Kramers-Kronig Transform test. The lowest frequency capacitance (C LF) value was obtained as C LF = 0.89 mFcm -2 for poly(Thy 2DTT). However, the highest C LF was obtained for the copolymer as C LF = 1.11 mFcm -2 for X Thy2DTT = 0.66 and 0.83. Potential application of the copolymer could be energy-storage devices. © 2012 The Electrochemical Society.