Comparative analysis of dielectric and optoelectronic properties in multifunctional PVDF/Ni-Mn ferrite nanocomposites

Abstract

Polymer-ferrite nanocomposite films were fabricated by incorporating annealed ferrite nanoparticles (Ni_0.2Mn_0.8Fe₂O₄) into polyvinylidene fluoride (PVDF) using a casting method. Infrared (IR) spectroscopy, UV–Vis spectrophotometry, broadband dielectric spectrometry (BDS), X-ray diffraction (XRD) and SEM micrograph characterized nanocomposite films. Structural analysis identified a mixture of PVDF in \(\alpha\) and \(\beta\) phases. With increasing ferrite concentration, the \(\beta\)-phase became more dominant, while the \(\alpha\)-phase became less prevalent. The average crystallite size of the films also grew from 20 to 27 nm with increasing ferrite content. Optical property analysis showed that the absorption coefficient \((\alpha )\) increased with both the energy of the incident photon and ferrite content. Meanwhile, the optical indirect band gap narrowed from 5.59 to 4.90 eV with increasing ferrite content. In addition, the refractive index \((n)\) increased with increasing ferrite concentration, ranging from 1.92 to 2.02. The dielectric properties were measured at room temperature and atmospheric pressure across an extensive frequency spectrum (10 Hz to 10 MHz), providing a comprehensive insight into the design and optimization of polymer-ferrite nanocomposite films for various applications.