α-MoO₃ Nanobelts Boosted the Structural, Optical, Thermal, and Dielectric Properties of PEO/PVP Blends for Emerging Optoelectronic/Energy-Storage Applications

This study presents a comprehensive investigation of the optical, thermal, structural, and electrical properties of poly-(ethylene oxide) (PEO)/polyvinylpyrrolidone (PVP) blends embedded with molybdenum trioxide nanobelts (MoO₃ NBs). The nanocomposites were fabricated via solution casting with varying concentrations of MoO₃ NBs to assess their influence on the polymer matrix. X-ray diffraction (XRD) analysis demonstrated the semicrystalline nature of PEO/PVP blends and revealed structural modifications induced by the nanofiller. Fourier transform infrared (FTIR) spectroscopy showed electrostatic interactions between the polymer matrix and MoO₃ NBs, facilitated by intermolecular and intramolecular hydrogen bonding. The indirect optical band gap decreased from 4.57 eV (pure blend) to 3.54 eV (4.0 wt % MoO₃), indicating enhanced optoelectronic properties. Thermogravimetric analysis (TGA) confirmed improved thermal stability upon nanobelt addition, while scanning electron microscopy (SEM) revealed a uniform dispersion of MoO₃ NBs within the polymer matrix. Furthermore, the nanocomposites exhibited significantly enhanced AC conductivity compared to the pure matrix, along with tunable dielectric properties consistent with non-Debye relaxation behavior. These findings highlight the potential of PEO/PVP-MoO₃ nanocomposite samples as tailorable dielectric materials for advanced applications in flexible solid-polymer electrolytes and high-performance energy-storage systems.