Preparation and luminescence properties of Mn4+-activated fluoride translucent ceramics for high-power light-emitting diodes

Mn 4+ -doped fluoride phosphors have attracted extensive attention in the white light-emitting diode (LED) field due to their efficient red emission, whereas significant luminescence thermal quenching restricts their development. Herein, we propose to improve the luminescence thermal stability of A 2 GeF 6 :Mn 4+ ( A = Rb + and K + ) by a translucent ceramic fabrication strategy. For the Rb 2 GeF 6 lattice, a phase transition from the P 6 3 mc space group to the P 3 ¯ $\bar 3$ m 1 space group occurs as the material transforms from powder to translucent ceramic, resulting in the disappearance of the zero-phonon line (ZPL) emission of Mn 4+ ions. During the translucent ceramic fabrication process, no phase transition is observed in the K 2 GeF 6 host. Notably, the PL thermal stability of the fluoride phosphors can be improved by the translucent ceramic fabrication strategy applied to both systems, with or without phase transitions. The LED-ceramic device also exhibits better performance than the LED-powder. After 40 min of high-power operation, the temperature of LED-ceramic rose six times less than that of LED-powder, demonstrating superior thermal stability. These results highlight the efficacy of the translucent ceramic strategy in enhancing the performance and stability of LEDs.