Synthesis and luminescent properties of new green Li2Mg1-xSiO4:xMn2+ phosphors

Abstract

Several Li2Mg1-xSiO4:xMn2+(x = 0.02, 0.04, 0.06, 0.08 and 0.10) phosphors were synthesized by a high temperature solid phase method. The structure, morphology, excitation and emission spectra, thermal stability, quantum efficiency, CIE color coordinates and fluorescence lifetime of these phosphors were studied by XRD, SEM, XPS and fluorescence spectrometry. The single pure Li2Mg1-xSiO4:xMn2+ phosphors were obtained after 3 h of heating at 650 °C, followed by 3 h of heating at 1050 °C. When the monitoring wavelength is 537 nm, excitation peaks appear at 364, 384 and 446 nm. When the monitoring wavelength is 446 nm, an emission peak appears at 537 nm. The luminous color of the Li2Mg1-xSiO4:xMn2+ phosphorscorresponds to the green area on the CIE color coordinate. With an increase of the Mn2+ ion doping concentration, the emission intensity increases first and then decreases. The quenching point of the Mn2+ ion concentration is x = 0.06. This was found by testing the thermal stability of the Li2MgSiO4:0.06Mn2+ phosphor. With an increase in temperature, the emission intensity gradually decreases. The energy transfer mechanism is an electric dipole-electric dipole interaction. The fluorescence lifetime increases first and then decreases with the increase of the Mn2+ ion doping concentration. The quantum efficiency reaches 26.3%. Therefore, Li2Mg1-xSiO4:xMn2+ green phosphors have potential applications in the field of white LEDs activated by near-ultraviolet chips.