Tuning the electrical and optical performance of PVA/PANI films via Fe2O3 nanorods for advanced energy storage and optoelectronic devices

Abstract

PVA/PANI-Fe₂O₃ nanocomposite films were successfully fabricated via a solution casting method with Fe₂O₃ nanorod loadings ranging from 1.0 to 4.5 wt% to tailor their structural, optical, and electrical properties for optoelectronic applications. XRD analysis revealed a progressive reduction in crystallite size (from ∼4.2 to ∼3.0 nm) and enhanced amorphous character, attributed to the disruption of the native hydrogen-bonding network in the polymer matrix by Fe₂O₃ nanorods. FTIR results confirmed strong interfacial interactions through hydrogen bonding between Fe₂O₃ and PVA/PANI chains. Optical measurements demonstrated a red shift in absorption edges and a significant narrowing of both direct and indirect band gaps, accompanied by an increase in Urbach energy, indicating the formation of localized states and increased structural disorder. These changes are associated with the modified electronic structure induced by Fe₂O₃ incorporation. Furthermore, dielectric analysis revealed multiple conduction regimes, with electrical conductivity improving by nearly two orders of magnitude due to the formation of interconnected charge transport pathways facilitated by the nanorods. Overall, the incorporation of Fe₂O₃ nanorods effectively tunes the physicochemical properties of PVA/PANI films, making them promising candidates for flexible optoelectronic and energy-related applications.