Realizing multicolor tunable photoluminescence in La2MgTiO6: Tb3+, Eu3+ phosphors via energy transfer and application for white light-emitting diodes

The achievement of multiple emission color phosphors has a significant importance in screen display, lighting devices, and multicolor imaging, but it still faces formidable challenges. In this work, double perovskite La2MgTiO6: Tb3+, Eu3+ phosphors with tunable emissions are designed and successfully synthesized. The obtained phosphors can emit intense green (Tb3+), red (Eu3+), and yellow emissions (Tb3+/Eu3+) via varying the co-doping concentration of Tb3+ and Eu3+. The CIE coordinates exhibit an excellent linear behavior in La2MgTiO6: Tb3+, Eu3+, revealing the possibility of linear adjustment of multiple emission colors. Detailed material characterization demonstrates that the multicolor tunable emission originates from energy transfer between Tb3+ and Eu3+. The decay dynamics analysis suggests that the multipole interaction between Tb3+ and Eu3+ is quadrupole-quadrupole interaction. A white light-emitting diode device with color rendering index of 84.7, correlated color temperature of 4684 K, and CIE coordinate of (0.3472, 0.3083) is fabricated by combining La2MgTiO6: Tb3+, Eu3+ yellow phosphor and BaMgAl10O17: Eu2+ blue phosphor. Our results reveal that La2MgTiO6: Tb3+, Eu3+ phosphors are promising luminescent materials in white light-emitting diodes.