Multiband orange–red photoluminescence of Eu3+ ions in new “114” LnBaZn3GaO7 and LnBaZn3AlO7 oxides

A new series of gallozincates LnBaZn3GaO7 (Ln=La, Nd, Sm, Eu, Gd, Dy, Y) and new aluminozincates LnBaZn3AlO7 (Ln=Y, Eu, Dy) have been synthesized. Their structure refinements show that these phases belong to the “114” series, with hexagonal P63mc space group previously described for SmBaZn3AlO7. The photoluminescence study of these oxides shows that the Eu3+ activated LnBaZn3MO7 oxides with Ln=Y, La, Gd; and M=Al, Ga exhibit strong magnetic and electric dipole transitions (multiband emission) which is of interest for white light production. These results also confirm that the site occupied by Eu3+ is not strictly centrosymmetric. The electric dipole transition intensity is the highest in GdBaZn3MO7 [M=Al, Ga]: 0.05Eu3+ as compared with other Eu3+ activated compositions. This is due to the layer distortion around GdO6 octahedra when compared with YO6 and LaO6 octahedra.

The projected structure consists of alternate stacked layers of Kagomé and Triangular type with statistical distribution of Zn and Ga atoms between two tetrahedral sites. Ba2+ present in anticuboctahedron coordinating with 12 oxygen atoms. The Eu3+ present in octahedral coordination with 3-fold rotational symmetry.Figure optionsDownload as PowerPoint slide