CaGdSbWO8:Sm3+: A deep-red tungstate phosphor with excellent thermal stability for horticultural and white lighting applications

Abstract

Recently, rare-earth doped phosphors have shown great promise in phosphor-converted light-emitting diodes (pc-LEDs) for horticultural and white lighting applications. Herein, a deep red-emitting tungstate phosphor, CaGdSbWO8 (CGSW):Sm3+ was obtained by a high-temperature solid-state reaction. The phosphor showed deep red-light emission at 647 nm, which was attributed to the 4G5/2–6H9/2 transition of Sm3+. Surprisingly, this phosphor displays excellent thermal stability. The emission intensity of the best sample doped with 0.05 mol Sm3+ was 93.95% at 480 K. Ultimately, the fabricated red LED revealed superior spectral matching with the plant pigments (chlorophyll A and chlorophyll B), high color purity (99.9%), and CIE chromaticity coordinates (0.630, 0.370). Moreover, the white light-emitting diode (w-LED) can be manufactured by the tri-chromatic method with a 410 nm chip, which has a high color rendering index (Ra = 88), CIE coordinates (0.336, 0.328). Thus, the Sm3+-doped CaGdSbWO8 tungstate phosphors have extensive application potential in the field of pc-LEDs.