PVA/HPMC/Fe₂O₃–MoO₃ nanocomposites with tunable optical, dielectric, and electrical properties for energy-storage and optoelectronic applications

Abstract

This work investigates the synergistic impact of iron oxide (Fe₂O₃) nanorods and molybdenum trioxide (MoO₃) nanobelts incorporated into a polyvinyl alcohol/hydroxypropyl methylcellulose (PVA/HPMC) blend via solution casting. The structure–property relationships of PVA/HPMC/Fe₂O₃–MoO₃ nanocomposites were analyzed using XRD, FTIR, UV–Vis spectroscopy, and electrical/impedance measurements. Structural analyses (XRD, FTIR) revealed reduced PVA/HPMC blend crystallinity and enhanced interfacial interactions, confirming effective integration of Fe₂O₃–MoO₃ nanofillers. Optical studies showed increased absorption, a bathochromic shift, and the appearance of a ligand-to-metal charge-transfer band, accompanied by reduced direct and indirect bandgaps due to defect-induced localized states and intensified interfacial charge transfer. Electrical and dielectric measurements indicated significant improvements in AC conductivity, charge transport, and dielectric constant, with the highest value (~908) achieved at 2.00 wt% nanofillers loading. Overall, the synergistic incorporation of Fe₂O₃ and MoO₃ nanofillers significantly enhances the optical, dielectric, and electrical performance of the PVA/HPMC matrix, making these nanocomposites promising for optoelectronic devices, flexible capacitors, and solid-state energy-storage applications. In addition, their improved dielectric response and charge transport characteristics suggest potential use in flexible sensors, electromagnetic interference shielding materials, and smart wearable electronic systems.