Luminescence and microstructures of Eu-doped in triple phosphate Ca8MgR(PO4)7 (R = La, Gd, Y) with whitlockite structure

Eu³⁺-doped triple phosphate Ca₈MgR(PO₄)₇ (R = La, Gd, Y) was synthesized by the general high temperature solid-state reaction. This phosphor was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and emission spectra. XRD and FT-IR analysis indicated that Ca₈MgR(PO₄)₇ (R = La, Gd, Y) crystallized in single-phase component with whitlockite-like structure (space group R3c) of β-Ca₃(PO₄)₂. Under the excitation of UV light, the phosphors show bright red emission assigned to the transition (⁵D₀ → ⁷F₂) at 612 nm. The crystallographic sites of Eu³⁺ ions in Ca₈MgR(PO₄)₇ (R = La, Gd, Y) host were discussed on the base of site-selective excitation and emission spectra, luminescence decay and its host crystal structure.