A promising yellow-emitting langbeinite-type phosphor NaBaY₂(PO₄)₃:Eu²⁺ for WLEDs

The development of novel phosphors with excellent luminescence properties for white light-emitting diodes (WLEDs) is always a formidable task. Compared with the traditional laborious and aimless "trial and error" experiments, a mineral-inspired prototype strategy can provide an efficient and accurate method. Herein, for the first time, a novel yellow-emitting phosphor NaBaY₂(PO₄)₃:Eu²⁺ was discovered using the mineral-inspired prototype strategy and cation substitution method. The phosphor was prepared via the high-temperature solid-state reaction method, and its crystal structure, luminescence properties and potential application for WLEDs were systematically investigated. The NaBaY₂(PO₄)₃ phase was derived from the K₂Mg₂(SO₄)₃-type mineral structure and a photoluminescence study revealed that the phosphor can emit bright yellow light with a maximum at 545 nm upon excitation at 351 nm. A WLED lamp was fabricated by the use of a blend of commercial blue-emitting BaMgAl₁₀O₁₇:Eu²⁺, yellow-emitting NaBaY₂(PO₄)₃:Eu²⁺ and red-emitting (Ca, Sr)AlSiN₃:Eu²⁺ phosphors with a 380 nm LED chip. The CIE, CCT, R_a and efficiency of the as-fabricated LEDs were measured to be equal to (0.366, 0.365), 4327 K, 91.2 and 40.8 lm W^-1, respectively. These results suggest that NaBaY₂(PO₄)₃:Eu²⁺ could be a promising candidate for n-UV WLEDs.