Synthesis and characterizations of sol-gel derived LaFeO3 perovskite powders

In this study, LaFeO3 perovskite powders were prepared via the sol-gel method in two different annealing temperatures (500 and 850 degrees C-according to DTA/TG results) for use in dye-sensitized solar cell applications. The thermal, structural, microstructural, particle size, optical and magnetic properties of the samples were characterized by differential thermal analysis (DTA)/thermogravimetric analysis (TG), Fourier transforms infrared spectrometer (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), particle size analysis (PSA), UV-Vis spectrometer and vibrating sample magnetometer (VSM). Our XRD findings show that the as-synthesized powders have an excellent crystallinity, and Scherrer's Equation is used for the estimation of crystallite sizes (within 26-29 nm). Samples were analyzed to reveal the valence states of elements through XPS. Survey scan XPS spectra and high-resolution XPS spectra of La-3d5 and Fe-2p for LaFeO3 samples are given. SEMs employed to observe surface morphologies of all xerogel and ceramic perovskite powder materials and SEM images were verified with PSA results. UV-Vis spectrometer analysis results show that the optical bandgap values (E-g) as measured on both particles were found 2.42 eV. In addition to all analyses, the powders show ferromagnetic behavior, and VSM analyses are used to determine ferromagnetic properties. These results, especially low bandgap, make LaFeO3 powders possible to further increase the performance and efficiency of perovskite-based cells.