Green biosynthesis and physicochemical characterization of Fe ₃ O ₄ nanoparticles using Punica granatum L. fruit peel extract for optoelectronic applications

Green biosynthesis of Fe ₃ O ₄ nanoparticles (NPs) using plant extract is desired, as the plant extract is safe for humans and the environment. In this study, magnetite Fe ₃ O ₄ NPs were greenly prepared using Punica granatum L. fruit peel extract as a reducing and capping agent. The effect of iron precursor contraction (0.01–0.1 M, FeCl ₃ ) was studied. The Fe ₃ O ₄ crystalline with an average crystallite size range from 21 to 23 nm was proven by X-ray powder diffraction. Scanning electron microscopy images showed that the synthesized Fe ₃ O ₄ NPs were mostly cubical. Ultraviolet-visible spectra showed that the prepared Fe ₃ O ₄ NPs exhibit absorption at 270 nm related to the Fe ₃ O ₄ NPs with a direct bandgap ranging from 1.87 to 2.26 eV and indirect bandgap of 2.16–2.48 eV. Fourier transform infrared spectroscopy analysis showed two characteristic absorption bands at 515 and 567 cm ⁻¹ , which proved the successful formation of Fe ₃ O ₄ . The proposed method using Punica granatum L. fruit peel extract offers an economical and environmentally friendly route for synthesizing many other types of metal oxides.