Synthesis, structure, and luminescence properties of layered oxychloride Ba3Y2O5Cl2

Abstract

We report the synthesis, crystal structure, and optical properties of a new layered perovskite oxychloride, Ba₃Y₂O₅Cl₂. The structural and electronic properties of the compound were studied and compared with those of related compounds, Ba₃RE₂O₅Cl₂ (RE = Sc, Gd, and Lu). Furthermore, the luminescence properties due to Eu-doping were investigated. Polycrystalline Ba₃Y₂O₅Cl₂ samples were successfully synthesized by a solid-state reaction. The space group of the compound was I4/mmm and the lattice constants were a = 4.3971(8) Å and c = 24.848(5) Å. The Y atom in this compound shifted toward the apical oxygen site owing to the asymmetric coordination of O and Cl. Moreover, large anisotropic displacements were observed at the O sites. The direct bandgap of the compound was 5.4 eV. As Y³⁺ ions with a distorted octahedron have an asymmetric coordination environment, both magnetic and electric dipole transitions were observed by doping Eu³⁺ to Y³⁺ sites. Ba₃Y₂O₅Cl₂:Eu 4% also showed a high internal quantum yield (IQY) (>70%). Therefore, considering the photoluminescence spectra and high IQY, this compound is a potential host lattice for optical materials.