Crystal structural and photoluminescence properties of Eu3+ doped MgZn2(PO4)2 phosphors by R+ (R = Li, Na, K) charge compensation

Eu3+ single doping and Eu3+, R+ (R = Li, Na, K) charge compensation co-doped orange-red MgZn2(PO4)(2) phosphors were prepared by high-temperature solid-state method. The effect of charge compensation agent R+ on the luminescence properties of MgZn2(PO4)(2):Eu3+ phosphors was investigated. The morphology and composition of the samples were characterized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), high-angle annular dark field (HAADF), and energy dispersive spectroscopy (EDS) techniques. The photoluminescence properties were studied using excitation and emission spectra. In this study, R+ is used as charge compensation to improve the emission intensity of Eu3+ and the physical explanation is given. The optimal doping concentration of Eu3+ in MgZn2(PO4)(2) was obtained to be 5 mol%. Under ultraviolet (396 nm) excitation, a strong orange-red luminescence corresponding to the D-5(0) ? F-7(i) (i = 1, 2, 3, and 4) transition of Eu3+ is observed. The CIE coordinates and decay lifetimes of typical samples are discussed. The chromaticity coordinates of the two samples were (0.604, 0.392) and (0.616, 0.382), respectively, both located in the orange-red region. The fluorescence lifetime of MgZn2(PO4)2 phosphors co-doped 5% Eu3+ and 5% R+ (R = Na and K) is obviously improved. The results show that MgZn1.9R0.05(PO4)(2):0.05Eu(3+) (R = Na and K) is a kind of orange-red phosphor with high efficiency under near ultraviolet excitation.