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.