Orange-red emitting Sr3LaTa3O12:Sm3+ phosphors with perovskite structure and high thermal stability for w-LEDs

A novel layered perovskite tantalate phosphor Sr 3 LaTa 3 O 12 :Sm 3+ (SLTO:Sm 3+ ) with orange-red emission was obtained for the first time via the solid-phase synthetic method. The phase purity, surface morphology , element distribution and luminescent properties of the SLTO: x Sm 3+ ( x  = 0.01 mol%–0.30 mol%) phosphors were investigated. Under 408 nm excitation, the optimum doped SLTO:0.10Sm 3+ phosphor emits orange-red light at 598 nm with the highest emission peak ( 4 G 5/2  →  6 H 7/2 ). The critical energy transfer distance is 1.687 nm. The prepared SLTO:0.10Sm 3+ phosphor has excellent thermal stability with temperature quenching temperature ( T 0.5  > 500 K) and high activation energy ( E a  = 0.25 eV). Through calculation, the chromaticity coordinates of all samples are concentrated in the orange-red area, and the color purity reaches 99%. The fabricated white light-emitting diode (w-LED) has a good correlated color temperature (5132 K), a high R a (89), and the CIE chromaticity coordinates (0.340, 0.327). Consequently, the superiority of orange-red-emitting tantalate SLTO:Sm 3+ phosphors for w-LEDs is demonstrated.