Preparation and luminescence properties of Mn ⁴⁺ ‐activated fluoride translucent ceramics for high‐power light‐emitting diodes

Abstract 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 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.