Microwave hydro/solvothermal synthesis of octahedron-like NaEu(MoO₄)₂ microarchitectures by EDTA-assisted and photoluminescence property

Octahedron-like NaEu(MoO₄)₂ microarchitectures with tetragonal scheelite-type structure have been successfully synthesized by a facile ethylene diamine tetraacetic acid (EDTA)-mediated microwave hydrothermal method. The as-prepared products were characterized by X-ray diffractometer, scanning electron microscope and photoluminescence. The particle size and morphology of NaEu(MoO₄)₂ can be tuned effectively by adjusting reaction temperature, reaction time, the amount of EDTA and ethylene glycol. Remarkably, the morphologies were the microflakes, micro-octahedrons, when the amount of EDTA was increased from 0 to 0.01 g at 180 °C. The excitation spectrum of the calcined NaEu(MoO₄)₂ micro-octahedron was observed with a maximum peak at near ultraviolet excitation (λex = 393 nm). Its emission spectrum was recorded under a excitation wavelength of 393 nm and exhibited the most intensitive red emission at 615 nm. This indicates the photoluminescence properties were strongly dependent on crystal morphology and crystallinity. So the calcined NaEu(MoO₄)₂ micro-octahedron has the potential to be applied in many LED devices.