Polycrystalline La_0.8Sr_0.2GaO₃ perovskite synthesized by sol–gel process along with temperature dependent photoluminescence

This work covers for the first time the protocol of the preparation of nominal composition La_0.8Sr_0.2GaO₃ by the sol–gel method using the citric acid. The structural and the optical properties were investigated, by X-ray diffraction (XRD), Fourier Transform infrared Spectroscopy (FT-IR) and Photoluminescence Spectroscopy (PL) techniques, respectively. The Rietveld refinement, from the X-ray diffraction patterns, showed the presence of La_0.63Sr_0.21Ga_0.95O_2.68 perovskite as a major phase which crystallizes in an Hexagonal structure and the appearance of minor impurity phase identified as Gallium Lanthanum Oxide (La₄Ga₂O₉) belonging to a Monoclinic structure. Two peaks indicating blue photoluminescence emission were observed at room temperature. One emission was related to secondary phase and the other was assigned rather to the oxygen deficiency in perovskite structure, leading to the formation of intermediary energy levels in the band gap.