Color Tuning Luminescence of Ce3+/Mn2+/Tb3+-Triactivated Mg2Y8(SiO4)6O2 via Energy Transfer: Potential Single-Phase White-Light-Emitting Phosphors

Abstract

Ce3+, Mn2+, and Tb3+-activated Mg2Y8(SiO4)6O2 (MYS) oxyapatite phosphors have been prepared via solid state reaction process. The Ce3+ emission at different lattice sites in MYS host has been identified and discussed. Under UV excitation, there exist dual energy transfers (ET), that is, Ce3+ → Mn2+ and Ce3+ → Tb3+ in the MYS: Ce3+/Mn2+/Tb3+ system. The energy transfer from Ce3+ to Mn2+ in MYS: Ce3+/Mn2+ phosphors has been demonstrated to be a resonant type via a dipole–quadrupole mechanism, and the critical distance (RC) calculated by quenching concentration method and spectral overlap method are 10.5 and 9.7 Å, respectively. The emitting colors of MYS: Ce3+/Mn2+/Tb3+ samples can be adjusted from blue to orange-red via ET of Ce3+ → Mn2+ and from blue to green via ET of Ce3+ → Tb3+, respectively. More importantly, a wide-range-tunable white light emission with high quantum yields (37–47%) were obtained by precise control of the contents of Ce3+, Mn2+, and Tb3+ ions. On the other hand, the CL properties of MYS: Ce3+/Mn2+/Tb3+ phosphors have been investigated in detail. The results indicate that the as-prepared MYS: Ce3+/Mn2+/Tb3+ phosphors have good CL intensity and CIE coordinate stability with a color-tunable emission crossing the whole visible light region under low-voltage electron beam excitation. In conclusion, the white light with varied hues has been obtained in Ce3+, Mn2+ and Tb3+-activated MYS phosphors by utilizing the principle of energy transfer and properly designed activator contents as well as the select of excitation wavelength under UV and low-voltage electron beam excitation.