Blue-Green-Yellow Color-Tunable Luminescence of Ce-, Tb-, and Mn-Codoped SrYNa(PO)F via Efficient Energy Transfer.

Tunable blue-green-yellow emitting SrYNa(PO)F (SYNPF):Ce,Tb,Mn phosphors have been prepared via a high-temperature solid-state reaction method. The structural and luminescent properties, energy transfer (ET) mechanism, and thermal quenching of the samples are investigated in detail. The ET from Ce to Tb and Mn in SYNPF is identified as the interaction of the electric dipole-quadrupole with ET efficiencies of 81.6% and 69.3%, respectively. The critical distances for Ce/Tb and Ce/Mn are calculated through the spectral overlap method to be 9.54 and 10.92 Å. Under UV excitation, high-efficiency tunable blue-green-yellow emissions from Ce to Tb and Mn can be obtained. Moreover, white light can also be achieved by adjusting the stoichiometry of Ce and Mn properly in the SYNPF phosphor. In addition, the temperature-dependent luminescence spectra exhibit good thermal quenching behaviors for the as-prepared phosphors. The above results suggest that SYNPF:Ce,Tb,Mn phosphors can act as color-tunable emission phosphors for potential applications in WLEDs.