Tunable band gap and ionic conductivity in PMMA and PANI blend with WO₃ nanocomposites for optoelectronics and energy storage devices

This work presents PMMA/PANI-WO₃ nanocomposites with tunable optical and electrical properties, designed for optoelectronic and energy storage applications. The novelty of this study lies in the incorporation of WO₃ nanoparticles into a PMMA/PANI blend, enabling a simultaneous enhancement of dielectric behavior, ionic conductivity, and optical response. XRD and FTIR analyses confirmed reduced crystallinity and strong polymer-filler interactions. Optical studies revealed a notable decrease in the band gap from 3.80 eV for pure PMMA/PANI to 3.18 eV at the highest WO₃ loading, accompanied by improved refractive index. Thermal analysis demonstrated enhanced stability, while impedance spectroscopy showed an increase in ionic conductivity by nearly three orders of magnitude (10⁻⁸ → 10^-5 S cm⁻¹), along with a higher dielectric constant, attributed to interfacial polarization and improved charge mobility. These results establish WO₃ as an effective nanofiller for tailoring multifunctional properties in polymer composites, making the developed materials promising candidates for flexible optoelectronic devices, supercapacitors, and advanced energy storage systems.