Synthesis, Structure, And Luminescence Properties Of Layered Oxychloride Ba3y2o5cl2

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) angstrom and c = 24.848(5) angstrom. 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.