Photoluminescence properties of a novel red-emitting nanowire phosphor Ba6Gd2W3O18:Eu3+

Novel double perovskite tungstate phosphors Ba6Gd2-xEuxW3O18 were synthesized via solid-state reaction method. The x-ray diffraction (XRD) patterns, scanning electronic microscope (SEM) images, photoluminescence (PL) excitation, emission spectra and PL decay curves were measured to characterize the as-prepared phosphors. XRD patterns indicate that the phosphors present pure phase with the cubic double perovskite structure (space group Fm-3m (225)) and the SEM image displays the nanowire structure with a diameter ranged from dozens to hundreds nanometers. The excitation and emission spectra demonstrate that Ba6Gd2-xEuxW3O18 phosphors present an intense charge transfer band at around 323 nm and a strong orange-red emission of Eu3+ (D-5(0) -> F-7(1) transition) at 593 nm. The optimum doping concentration of Eu3+ ions in Ba6Gd2-xEuxW3O18 phosphors is around 20 mol% and the major mechanism for concentration quenching is the quadruple-quadruple interaction.