Preparation of luminescent nanosized NaEu(MoO₄)₂ incorporated in amorphous matrix originated from zeolite

Novel luminescent material has been prepared by the reaction of Eu³⁺ and molybdate species in the matrix of faujasite (FAU) type zeolite X and successive calcination. Eu³⁺ exchanged FAU was reacted with MoO₃ in the solid-state at 723 K, giving a precursor. By calcining it at 1073 K, different crystalline phases were derived depending on MoO₃-loading levels. Scheelite type crystal of NaEu(MoO₄)₂ was formed at high MoO₃-loading levels, whereas europium sodalite was formed at low loading levels. For the former sample, X-ray diffraction analysis and transmission electron microscopy revealed that the nanosized NaEu(MoO₄)₂ was dispersed homogeneously within amorphous aluminosilicate matrix originated from FAU. The amorphous particles containing NaEu(MoO₄)₂ maintained the original morphology, which the starting FAU particles possessed. The emission intensity of nanosized NaEu(MoO₄)₂ in the matrix was one order higher than that of europium sodalite. The emission lifetime of nanosized NaEu(MoO₄)₂ (0.39 ms) in the matrix was longer than that of bulk NaEu(MoO₄)₂ (0.35 ms) fabricated by conventional solid-state processes.