Electrochemical polymer synthesis using thiophene and pyrrole/carbazole: Their electrochemical behaviours and capacitor performance

Abstract

In this study, carbazole-derived monomers were synthesized on ITO-coated PET via electrochemical reactions and conductivity measurements of the resulting polymeric films were performed by UV, FT-IR, NMR, TG-DTG, SEM and AFM analyses. Their spectroelectrochemical properties were investigated. The carbazole (C) based thiophene (Th) polymer abbreviated as pThC and its copolymer with pyrrole (Py), named as pThC-Py were obtained by electrochemical polymerization method. The surface stability of the resulting polymer films was good depending on time. The contact angle (CA) between the water and theco- polymer surface was determined by dropping 6.09 μL of pure water and CA average was calculated as 68.19° < 90°. According to the thermal analysis data of the polymers, the thermal stability of the pThC-Py was better than pThC as it had higher thermal decomposition temperature. Comparisons of electrical conductivity measurements of the polymer films were made depending on the temperature (25, 50 and 90 °C). Due to increasing temperature, the electrical conductivity of pThC-Py film was read as 29.3 S/cm at 90 °C, and also the electrical conductivity values of the pThC-Py were determined as 1.92 × 10−2 S/cm at 25 °C and 14.2 S/cm at 50 °C. Because of the high electrical conductivity of the pThC-Py, its capacitor performance was tried to be determined from cyclic voltammetric measurements. According to the voltammetric results, the power density (P) and the energy density (E) values of the synthesized substance were calculated as 290.532 W/g and 9.684 Wh/g, respectively. This indicates that the amount of energy the material storable is relatively high. Moreover, it is possible to say that it can be included in the classical capacitor class and in the supercapacitor category by improving its features. Moreover, since the electrical conductivity of pThC-Py is quite good, it is thought that it may be suitable for use in electronic devices.