Luminescence and energy transfer properties of novel Na2.5Y0.5Mg7(PO4)6: R (R = Eu2+, Tb3+ and Mn2+) phosphors

Abstract

A series of Eu²⁺, Mn²⁺ and Tb³⁺ singly and co-doped Na_2.5Y_0.5Mg₇(PO₄)₆ phosphors have been prepared by the solid-state reaction method. X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) have been used to characterise the crystal structure, morphology and composition of the as-prepared samples. The emission intensities of Mn²⁺ and Tb³⁺ are enhanced due to an efficient energy transfer from Eu²⁺ to Mn²⁺ and Tb³⁺ in Na_2.5Y_0.5Mg₇(PO₄)₆. In addition, the energy transfer mechanisms between Mn²⁺, Tb³⁺ and Eu²⁺ have been demonstrated. Similarly, white light emission in the Na_2.5Y_0.5Mg₇(PO₄)₆ host can be realized by adjusting the co-doped concentration of Eu²⁺, Tb³⁺ and Mn²⁺. The results indicate that the as-prepared phosphors have a great prospect as phosphor-converted materials for light-emitting diodes.