Study of Nanostructural, Electrical, and Optical Properties of Mn_0.6Fe_2.4O₄–PEG/PVP/PVA Ferrogels for Optoelectronic Applications

Ferrogels based on polyvinylpyrrolidone/polyvinyl alcohol (PVP/PVA) matrices with Mn_0.6Fe_2.4O₄–polyethylene glycol (Mn_0.6Fe_2.4O₄–PEG) were synthesized using the freezing–thawing method. The phase structure and morphology of ferrogels with Mn_0.6Fe_2.4O₄–PEG filler were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The Mn_0.6Fe_2.4O₄–PEG/PVP/PVA ferrogel was characterized using small-angle X-ray scattering to determine the distribution of Mn_0.6Fe_2.4O₄–PEG nanoparticles through two-lognormal data analysis; the semicrystallite distribution of the PVP/PVA was investigated using the Beaucage and Teubner–Strey models. The optical and electrical properties of the Mn_0.6Fe_2.4O₄–PEG nanoparticles were characterized using a UV–Vis spectrophotometer. The XRD analysis showed that the Mn_0.6Fe_2.4O₄–PEG exhibits an inverse-spinel cubic structure with an average particle size of 10.2 nm. This result was corroborated by TEM analysis, which revealed an average size of 10.9 nm through the Image-J software analysis. The two-lognormal method was used to analyze the distribution of Mn_0.6Fe_2.4O₄–PEG nanoparticles in the ferrogel, revealing a secondary particle size of approximately 9.8 nm. These secondary particles are, on average, evenly arranged with respect to the primary particles with a diameter of 3.3 nm. UV–Vis data analysis showed that the refractive index and energy gap of the Mn_0.6Fe_2.4O₄–PEG nanoparticles were approximately 2.79 and 2.24 eV, respectively. The optical conductivity and electrical conductivity calculated from the refractive-index and energy-gap data were 1.27 × 10⁸ and 70 Ω⁻¹ cm⁻¹, respectively. These results indicate that the Mn_0.6Fe_2.4O₄–PEG nanoparticles exhibit strong potential for use as a base material in optoelectronics applications.