An intense single-component warm-white-light Sr3Lu(PO4)3:Dy3+ phosphor for white UV-LEDs

A novel single-phase white-light-emitting phosphor Sr3Lu(PO4)(3):Dy3+ was prepared by conventional solid-state reaction, and the phases and luminescent properties were well characterized. The excitation spectrum shows that Sr3Lu(PO4)(3):Dy3+ system can be efficiently excited at wavelength ranging from 350 to 410 nm, which is well-matched with ultraviolet (UV) light-emitting diode chips. Under the UV excitation of 350 nm, the phosphor exhibits intense warm white luminescence with dominating emissions at 482 and 575 nm, corresponding to F-4(9/2)-H-6(15/2), F-4(9/2)-H-6(13/2) transitions, respectively. With increasing Dy3+ concentration in Sr3Lu(PO4)(3):Dy3+, the CIE coordinates of phosphors change a little in the warm white region and the lifetime decreases from 0.747 to 0.404 ms. Concentration quenching occurs when the Dy3+ concentration is beyond 0.08. The critical transfer distance was calculated to be about 18.3 and the concentration quenching mechanism was demonstrated to be the electric dipole-dipole interaction according to Dexter's theory. The temperature dependence of photoluminescence properties were investigated from 25 to 200 A degrees C and the as-prepared Sr3Lu(PO4)(3):Dy3+ phosphor showed good thermal quenching properties.