Synthesis And Luminescant Properties Of Ba₉Lu₂Si₆O₂₄:Re Phosphors For White LEDs

Due to the low power consumptions, environment-friendly, long lifetimes, high luminous efficiencies, small volume and impact resistance, white LEDs (light-emitting diode) have been the new generation light source. The most mature way to achieve white LED is the phosphor-converted method. Thus, the fabrication of phosphors used for white LED and the luminescent properties were paid more attention. Therefore, we did some work to aim at a number of deficiencies of phosphors for white LED application and systematically investigated the synthesis, structure and luminescent properties of Ba9Lu2Si6O24:RE phosphors:1. A green phosphor Ba9Lu2SieO24:Eu2+ for white LED:Novel green-emitting phosphor Ba9Lu2Si6O24:Eu2+was synthesized by conventional solid-state reaction method. The phase formation of as-prepared samples were investigated by X-ray powder diffraction. The photoluminescence emission (PL) and excitation (PLE) spectra indicated that the phosphor could be efficiently excited by UV-blue light (250-480 nm), and presented a broad green emission band with three-band profile suggesting three different emission centers occupied by Eu2+. The critical quenching concentration of Eu2+was determined to be 0.15 mol and the concentration quenching mechanism was also investigate. Furthermore, the phosphor has good thermal stability property, and the thermal activation energy for thermal quenching in the Ba9Lu2Si6O24:0.15Eu2+ was also measured to be 0.327 eV. The result indicates that Ba9Lu2Si6O24:Eu2+is a promising green-emitting phosphor for white LEDs.2. A single-phased phosphor Ba9Lu2Si6O24:Bi3+,Eu3+ for white LED:A series of single-phased Bi3+,Eu3+codoped Ba9Lu2Si6O24 phosphors were prepared via high-temperature solid-state reaction. The luminescent properties and energy transfer mechnism were systematically investigated. Tuning of the content of Eu3+, Tuning of the content of Eu3+, these phosphors could be effectively excited by ultraviolet light (310-390 nm) and emitted color tunable luminescence from blue to white then to red light. Energy transfer effciency from Bi3+ to Eu3+ could reach 88% under 335 nm light excitation in this Ba9Lu2Si6O24 (BLSO) host matrix. Our results demonstrate that these color tunable phosphors may find potential application in solid-state lighting and other areas.