A broadband yellow Yb2+-doped oxynitride phosphor for high-performance white light-emitting diodes

Abstract

Here, we report a yellow phosphor (Ba,Sr)Si₃Al₃O₄N₅:Yb²⁺, which not only has an ultra-high internal quantum efficiency of 86.9% and a full width at half maximum of 146 nm (4712 cm⁻¹), but also shows superior water resistance and thermal stability. The thermal quenching activation energy of the optimized Ba_0.5Sr_0.4Si₃Al₃O₄N₅:0.1Yb²⁺ phosphor was determined to be 0.25 eV. By combining a 450 nm chip with (Ba,Sr)Si₃Al₃O₄N₅:Yb²⁺, a single-phosphor-converted warm white light-emitting diode with CIE chromaticity coordinates of (0.3289, 0.3539), a correlated colour temperature of 5650 K and a colour rendering index of 80 under a driven current of 150 mA was successfully fabricated. A high temperature aging test demonstrated the excellent luminous efficacy (98.5%@288 h) and CIE chromaticity coordinate stability of the white light-emitting diode.