Integrating the optical, conductivity, dielectric and thermal properties of silicon dioxide/polyindole nanocomposites for optoelectronic devices

Our study deals with the synthesis of silicon dioxide (SiO₂) reinforced polyindole (PIN) nanocomposite by a simple in-situ polymerization method for tuning the optical, thermal and electrical properties. The characteristics of the nanocomposites were investigated using FTIR, UV, SEM, XRD, DSC, TGA and various electrical properties were carried out by an impedance analyser. FTIR analysis revealed that SiO₂ nanoparticles interact with the PIN matrix by changing the wavenumbers of polar groups. The UV–visible spectroscopy investigation revealed that the optical energy gap decreased as the nanofiller content increased up to a particular concentration of SiO₂. The integration of nanoparticles in the PIN matrix resulted in a semi-crystalline structure, as confirmed by XRD studies. The SEM examination demonstrated that the nanoparticles were distributed uniformly throughout the conducting polymer matrix, suggesting homogenous dispersion. The DSC and TGA findings revealed that the glass transition temperature and thermal resistance of the nanocomposites were improved with the addition of SiO₂. The dielectric characteristics and AC electrical conductivity increased considerably as temperature and SiO₂ loading increased. The activation energy computed from the Arrhenius equation drops with frequency, and the minimum activation energy was observed for 6 wt% PIN/ SiO₂. The conductivity of PIN/SiO₂ nanocomposites was greater than that of pure polymer. These results suggest that the in-situ synthesised PIN/ SiO₂ nanocomposites show improved thermal stability, optical properties, glass transition temperature, AC conductivity and dielectric characteristics and could be suggested in optoelectronic and energy storage devices.