A Single-Component White-Emitting CaSr2Al2O6:Ce3+, Li+, Mn2+ Phosphor via Energy Transfer

A series of single-component Ce3+, Li+, Mn2+ ions codoped color-tunable CaSr2Al2O6 phosphors were synthesized by a high-temperature solid-state reaction, and the photoluminescence properties as well as the energy transfer mechanism from Ce3+ to Mn2+ ions have been investigated in detail. The Ce3+ activated phosphors have strong absorption in the range of 250–420 nm and can give a blue emission centered at about 460 nm. When Mn2+ ions are codoped, the emission of CaSr2Al2O6:Ce3+, Li+, Mn2+ phosphors can be tuned from blue to red through adjusting the doping concentration of the Mn2+ ions, under the irradiation of 358 nm. When the concentration of Mn2+ is increased to 0.02, a warm-white light can be obtained with good CIE coordinates of (0.388, 0.323) and a low CCT of 3284 K. The energy transfer mechanism from the Ce3+ to Mn2+ ions is demonstrated to be a quadrupole–quadrupole interaction based on the analysis of the decay curves of the phosphors. The thermal quenching stability was also investigated. The results indicate that CaSr2Al2O6:Ce3+, Li+, Mn2+ samples might have potential applications in w-LEDs.