Synthesis and luminescence properties of novel red-emitting Na2ZnSiO4:Eu3+ phosphor with intense 5D0 → 7F4 transition and high quantum yield

Abstract Novel red-emitting Eu 3+ -doped Na 2 ZnSiO 4 phosphors were synthesized by a conventional high temperature solid reaction. The crystal structure was confirmed by X-ray diffraction (XRD) and the morphology was examined by scanning electron microscopy (SEM). The luminescence properties of Na 2-x Zn 1-x SiO 4 :xEu 3+ (NZS:xEu) phosphors were investigated by photoluminescence excitation (PLE), emission (PL) spectra and decay curves. The phosphors exhibit abnormal intense red emission which located at 702 nm due to the 5 D 0 → 7 F 4 transition of Eu 3+ under the excitation of 393 nm and it makes the CIE chromaticity coordinates of the phosphors to fall in a red region. This phenomenon may be explained by the highly polarizable chemical circumstance. The optimum Eu 3+ doping concentration of NZS:xEu is determined to be x = 0.08. The critical distance between Eu 3+ was calculated to be 13.36 A. The concentration quenching mechanism can be interpreted by the quadrupole–quadrupole interaction of Eu 3+ ions. The decay curves show double exponential behavior for all concentrations of Eu 3+ ions and the lifetimes varied from 0.67 to 1.3 ms when the Eu 3+ doping concentration increased in the range of 4–12 mol%. The quantum yield (QY) of Na 2 ZnSiO 4 :0.08Eu 3+ phosphor is calculated to be as high as 88.76%. The present work suggests that Na 2 ZnSiO 4 :Eu 3+ phosphor is a promising candidate as a red component for NUV LEDs application.