Effect of NH₄Cl flux used to synthesize double perovskite BaLaMgSbO₆:Eu³⁺ phosphor by solid-state reaction method

Eu³⁺ ions activated BaLaMgSbO₆ phosphors were successfully synthesized by the solid-state reaction method using NH₄Cl as the flux. The influence of NH₄Cl, structure, morphology and photoluminescent properties of as-prepared powders were investigated in detail. Long-range ordering of B-site cations existed in this double perovskite. With increasing the amount of NH₄Cl, the morphology of phosphors changed from regular polyhedron shape to globoid shape. Broad and strong A _1g mode existed in the Raman spectrum. The absorption intensity of charge transfer band was higher than the intensity of characteristic f–f absorption of Eu³⁺. The luminescence intensity of ⁵D₀–⁷F₂ (electric dipole transition) was much higher than that of ⁵D₀–⁷F₁ (magnetic dipole transition). The optimum adding amount of NH₄Cl was 10.0 wt% while excited by the CTB and the phosphor emitted intense red light. The CIE chromaticity coordinates indicated that the phosphors showed good color purity. Therefore the synthesized phosphor is a potential light conversion red material for light emitting diode.