Blue–Green–Yellow Color-Tunable Luminescence of Ce 3+ -, Tb 3+ -, and Mn 2+ -Codoped Sr 3 YNa(PO 4 ) 3 F via Efficient Energy Transfer

Tunable blue–green–yellow emitting Sr 3 YNa(PO 4 ) 3 F (SYNPF):Ce 3+,Tb 3+,Mn 2+ 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 3+ to Tb 3+ and Mn 2+ 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 3+ /Tb 3+ and Ce 3+ /Mn 2+ 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 3+ to Tb 3+ and Mn 2+ can be obtained. Moreover, white light can also be achieved by adjusting the stoichiometry of Ce 3+ and Mn 2+ 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 3+,Tb 3+,Mn 2+ phosphors can act as color-tunable emission phosphors for potential applications in WLEDs.