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

A novel layered perovskite tantalate phosphor Sr3LaTa3O12:Sm3+ (SLTO:Sm3+) 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:xSm(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) -> H-6(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:Sm3+ phosphors for w-LEDs is demonstrated. (c) 2023 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.