Preparation and characterization of lanthanum-based perovskite oxides LaMO3 (M=Fe, Cr, Mn) thin films by electrophoretic deposition

In this study, we report the fabrication and characterization of LaMO3 (M = Fe, Cr, Mn) perovskite thin films deposited on FTO substrates via electrophoretic deposition (EPD). The x-ray diffraction (XRD) patterns showed the formation of the orthorhombic structure for LaFeO3 and LaCrO3 films and the trigonal structure for the LaMnO3 film. The field-emission scanning electron microscopy (FE-SEM) micrographs revealed nano-spherical particles with an average grain size of about 50 nm covering the LaMnO3 surface with fewer porosities compared to the other films. Moreover, the LaMnO3 film exhibited a higher transparency in the visible region (similar to 84%). The estimated bandgaps of LaFeO3, LaCrO3, and LaMnO3 perovskite films were found to be 2.17, 3.18, and 2.92 eV, respectively. In addition, the refractive indices of all deposited films were calculated using five empirical models that relate the refractive index to the bandgap, which consistently revealed a decrease in refractive index with an increase of bandgap energy This study holds significant implications for the field of perovskite thin films as we contribute new insights into the fabrication of lanthanum-based perovskite thin films using the EPD technique. The comprehensive characterization of micro-structural, morphological, and optical properties provides valuable information for understanding the structure-property relationship in these materials. Furthermore, the determination of bandgaps and refractive indices enhances our understanding of the optical properties of perovskite films. The findings from this study pave the way for potential applications in optoelectronic devices, where fine-tuning of material properties is critical for optimal device performance.