The design and synthesis of new double perovskite (Na,Li)YMg(W,Mo)O 6 :Eu 3+ red phosphors for white light-emitting diodes

Abstract Doubly ordered double perovskites with AAʹBBʹO 6 stoichiometry are promising new host materials for Eu 3+ activator ions. In this paper, double perovskite (Na,Li)YMg(W,Mo)O 6 :Eu 3+ phosphors were synthesized by a high-temperature solid-state method and the effect of cation substitutions in this series of monoclinic-type NaYMgWO 6 compounds was investigated in order to control the photoluminescence properties. The composition modulation and structural evolution of (Na,Li)YMg(W,Mo)O 6 :Eu 3+ were studied by powder X-ray diffraction and Rietveld refinement. The microstructure and composition of the phosphor materials were characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. All compounds' photoluminescence properties were measured, and the luminescence properties were related to the structural properties of the materials. The (Na,Li)YMg(W,Mo)O 6 :Eu 3+ phosphors emit intense red light dominated by the 5 D 0 → 7 F 2 transition at ∼618 nm, along with other characteristic transitions from Eu 3+ 4f-4f transitions when excited at ∼395 nm and ∼466 nm. The red emission intensity of Eu 3+ reaches a maximum for LiYMgW 0.9 Mo 0.1 O 6 :Eu 3+ phosphor, which exhibits high quantum efficiency and excellent thermal stability. The obtained results suggest that these new double perovskites doped with Eu 3+ are promising red phosphor candidates for white light-emitting diodes.