Tailoring physical properties and electrochemical performance of polyaniline thin films via chemical bath deposition

Abstract

This study focuses on the properties of polyaniline (PANI) thin deposited onto glass substrates using a chemical bath method. The films were prepared under the same conditions, except for the type of oxidant used. Three oxidants were utilized: potassium per-sulfate (KPS), sodium per-iodate (NAIO4), and ferric chloride di-hydrated (FeCl3·2H2O). X-ray diffraction (XRD) analysis confirmed that all deposited films had an amorphous structure. Fourier-transform infrared spectroscopy (FT-IR) confirmed the presence of PANI films, as indicated by the recorded peaks. Scanning electron microscopy (SEM) was employed to study the surface structure and morphologies of the films, revealing nano-structured grains with varying average grain sizes depending on the oxidant type. The elemental composition of the films was analyzed using X-ray photoelectron spectroscopy (XPS). The optical band gap values were determined to be 4.06 eV, 3.93 eV, and 3.96 eV for FeCl3·2H2O, NAIO4, and KPS oxidants, respectively. The refractive index and extinction coefficient were also calculated from optical data, showing significant variations with changes in the oxidant type. The high frequency dielectric constant of the films was estimated using the Spitzer-Fan model, resulting in values of 5.15, 3.24, and 474 for FeCl3, NAIO4, and KPS oxidants, respectively. Additionally, cyclic voltammetry studies revealed that PANI/glass films grown using NAIO4 exhibited the highest specific capacity. Further investigation of PANI/FTO/glass films showed a specific capacity estimated to be 100 Fg-1 for this particular film configuration.