Structural Analysis and Temperature-Dependent Impedance Behavior of BiFeO₃ Nanoparticles for PV Application

Abstract

Silicon semiconductor remains the principal material for commercial PV (photovoltaic) cells. Alternative PV materials are being actively explored to reduce dependence on silicon-based PV cells and improve future cell performance. Bismuth ferrite (BiFeO₃, BFO) has attracted consideration as a lead-free multifunctional oxide material for PV applications because of its preferable bandgap of 2.0 to 2.7. In this work, BiFeO₃ nanoparticles were synthesized by the sol–gel method and annealed at 600 °C, and their structural, morphological and impedance characteristics were examined. X-ray diffraction (XRD) analysis confirmed the formation of crystalline BiFeO₃ nanoparticles, confirming the rhombohedral R3c phase, with prominent diffraction peaks around 31.8° and 32° (2θ). Field-emission scanning electron microscopy (FESEM) revealed the surface morphology and particle size of 138 nm of the synthesized nanoparticles. The impedance behavior of BiFeO₃ was further investigated through frequency-dependent impedance measurements at 100, 200 and 300 °C. The impedance response showed a clear dependence on frequency and temperature. At 100 °C, impedance decreased continuously with increasing frequency. However, at 200 and 300 °C, the impedance showed dual behavior, first increased and then decreased with frequency. The structural development, nanoparticle morphology and temperature-dependent impedance response show that sol–gel-synthesized BiFeO₃ nanoparticles may be useful for PV cells and related electronic devices.