Tunable luminescence and energy transfer properties in Ca8MgLu(PO4)7:Ce3+,Tb3+,Mn2+ phosphors

Ca8MgLu(PO4)(7):Ce3+,Tb3+,Mn2+ (abbreviated as CMLP:Ce3+,Tb3+,Mn2+) phosphors were synthesized by a high-temperature solid-state method. X-ray diffraction (XRD), photoluminescence (PL) spectra, GSAS structural refinement, and absolute quantum yield and lifetimes were used to characterize the samples. Increasing the Ce3+ doping concentration in the CMLP host shifts the emission peak from 360 to 374 nm. Under UV excitation, the energy transfers (ETs) from Ce3+ to Tb3+ and from Ce3+ to Mn2+ in the CMLP host occurred mainly via a dipole-quadrupole mechanism, and the critical distances of the ion pairs (R-C) were calculated by the quenching concentration method and spectral overlap method, respectively. The emission colors of the CMLP:Ce3+,Tb3+,Mn2+ samples could be adjusted from blue to green, and eventually to orange-red by the ET between Ce3+ and Tb3+/Mn2+. Moreover, a white light emission tunable over a wide range was obtained by precisely controlling the contents of Ce3+, Tb3+ and Mn2+. Temperature dependent luminescence spectra proved the good thermal stability of the as-prepared phosphor. Based on the good PL properties and varied hues of the CMLP host achieved by adjusting the doping concentration of the activators (Ce3+, Tb3+, Mn2+), CMLP might be promising as a host material for solid-state lighting and display fields.