Copolymer versus bilayer composite: Electrochemical, electrochromic and capacitive properties of benzotriazole and edot containing conjugated polymers

In this study, benzotriazole-based homopolymer (P-TBtz), copolymer (C-TBtzEdot), and bilayer composites (BTBtzEdot and B-EdotTBtz) were prepared by electrochemical polymerization. B-TBtzEdot and B-EdotTBtz differ only in the sequential deposition orders onto the ITO electrode. Wise selected materials successfully performed their jobs: TBtz introduced a multichromic property to polymer films and Edot improved the charge storage capacity. Electrochemical characterizations of resulting conjugated polymer films were performed by cyclic voltammetry (CV), chronopotentiometry, chronoamperometry, and electrochemical impedance spectroscopy (EIS). For optical and morphological characterization, UV-vis spectroscopy and scanning electron microscopy (SEM) were used, respectively. According to SEM images, all films have different morphologies. Moreover, upon applied potential, change in the absorption spectra and color change was monitored. Besides, the capacitance value of the polymer films was calculated from cyclic voltammogram and galvanostatic charge-discharge curves. C-TBtzEdot had the highest capacitance value as 97.5 F/g at 2 mV/s and 92 F/g at 0.5 A/g.