A new rare-earth oxyborate Ba3BiPbEuO(BO3)4 and the luminescence properties of the Ba3BiPbY1−xEuxO(BO3)4 phosphors

Abstract

A new rare-earth oxyborate Ba₃BiPbEuO(BO₃)₄ was prepared, and its crystal structure was established by the single-crystal X-ray diffraction method with the following structural data: P6₃/mmc, a = 5.4305(1) Å, c = 26.3501(3) Å, V = 672.96(3) ų and Z = 2. This is a layered material containing two types of layers: one is formed by corner-sharing EuO₆ octahedra and BO₃ triangles and the other is composed of corner- or edge-sharing (Bi/Pb)O₇ hexagonal pyramids and BO₃ triangles. These layers and their equivalent partners are alternately stacked along the c-axis, with Ba²⁺ cations situated in between and within the layers. Furthermore, the phase composition, morphology, and IR, Raman, XPS, and UV–vis absorption spectra of this compound were studied. In addition, solid solutions of Ba₃BiPbY_1−xEu_xO(BO₃)₄ (0 ≤ x ≤ 1) were prepared via the solid-state reaction method and their photoluminescence properties were investigated. Ba₃BiPbYO(BO₃)₄ and Ba₃BiPbEuO(BO₃)₄ showed blue and reddish-orange luminescence when excited at 242 and 394 nm, respectively. By doping Eu³⁺ into the Ba₃BiPbYO(BO₃)₄ matrix and changing the Eu³⁺ doping concentration, luminescence color tunability from blue to orange-red was realized in Ba₃BiPbY_1−xEu_xO(BO₃)₄ phosphors under excitation at 331 nm. This kind of material with color variability may have potential application in field-emission displays.