Aliovalent M site substitutions of [PO4]3− and [HfO4]4− for [AlO4]5− and [GaO4]5− in the Sr3MO4F-type anti-perovskite oxyfluoride

Abstract

Rare earth-free phosphor materials have been synthesized via aliovalent doping of [PO4]3− and [HfO4]4− for [AlO4]5− and [GaO4]5− in the Sr3MO4F host lattice (space group I4/mcm). High temperature synthesis was used to synthesize the novel products Sr2.5-xBa0.5Al1-xPxO4F (0.05 ≤ x ≤ 0.15), Sr2.5-xBa0.5Ga1-xPxO4F (0.05 ≤ x ≤ 0.15) and (0.025 ≤ x ≤ 0.075). The structures of these oxyfluorides were analyzed via powder X-ray diffraction (PXRD) and neutron powder diffraction (NPD), and their photoluminescent properties were analyzed through spectrofluorimetry before and after being treated under reducing conditions. Optimal doping was found at a concentration of x = 0.10 for Sr2.5-xBa0.5Al1-xPxO4F (a = 6.8762(4) Å; c = 11.1273(6) Å) resulting in a maximum emission at 454 nm when excited at 214 nm and x = 0.05 for the Ga analog (a = 6.87591(7) Å; c = 11.3722(2) Å) corresponding to an emission centered around 529 nm from excitation with 227 nm. When doping with Hf4+ the optimal concentration for was x = 0.025 (a = 6.8607(1) Å; c = 11.1682(3) Å), resulting in a broad emission between 410–600 nm when excited at 251 nm. © 2019 The Electrochemical Society