Impact of Mn-Ni spinal ferrite nanoparticles on the structural, morphological, surface roughness, and optical parameters of polyvinyl alcohol for optoelectronic applications.

Herein, polyvinyl alcohol (PVA) acts as a host matrix for manganese-nickel ferrite (MnNiFeO) nanoparticles (NPs). Oxalate precursors and a solution-cast method were used to produce a MnNiFeO spinel structure and PVA-MnNiFeO films, respectively. X-ray diffraction (XRD), scanning electron microscopy, optical microscopy (OM), a surface roughness tester, and FT-IR spectroscopy were used to identify the structure and morphology of the PVA-MnNiFeO films. XRD confirmed the formation of MnNiFeO spinel, and its additive into the PVA matrix causes an increase in the PVA amorphousity. The PVA-MnNiFeO film's transmission and absorption spectra were recorded with the help of a UV-visible spectrophotometer. The addition of 4%MnNiFeO to PVA resulted in a decrease in the optical bandgap from 5.53 eV to 4.83 eV. The Urbach energy increases from 0.46 eV for pure PVA to 2.14 eV for PVA-4%MnNiFeO, indicating a rise in the defect density. In addition, the refractive index and extinction coefficient were calculated theoretically and were found to increase as the MnNiFeO content increases in the PVA matrix.