Tungstate flux-grown Y₁₀W₂O₂₁:Eu³⁺ phosphors with enhanced particle size and luminescence properties

Eu_0.5Y_9.5W₂O₂₁ strong red emission phosphors were synthesized via a conventional solid-state reaction method with environmentally friendly tungstate flux (M₂WO₄, M=Li, Na, K). The growth process of the Eu_0.5Y_9.5W₂O₂₁ phosphors was studied using X-ray diffraction, scanning electron microscopy, and thermogravimetry/differential thermal analysis. The photoluminescence properties, including emission and excitation spectra and thermal stability, were also investigated. The experimental results indicate that the particle size and morphology of the Eu_0.5Y_9.5W₂O₂₁ phosphors depend on the type and content of tungstate flux. The luminescence intensities of the phosphors were effectively enhanced by the tungstate flux. The results also show that the Eu_0.5Y_9.5W₂O₂₁ phosphors are very suitable for use in near-ultraviolet light-emitting diode (LED) chips (392 nm) and blue LED chips (465 nm).