Novel Mn-Activated KNbMoF (0 ≤ ≤ 0.15) Solid Solution Red Phosphors with Superior Moisture Resistance and Good Thermal Stability.

Nowadays, Mn-activated fluoride red phosphors with excellent luminescence properties have triggered tremendous attentions for enhancing the performance of white light-emitting diodes (WLEDs). Nonetheless, the poor moisture resistance of these phosphors impedes their commercialization. Herein, we proposed the dual strategies of "solid solution design" and "charge compensation" to design KNbMoF novel fluoride solid solution system, and synthesized the Mn-activated KNbMoF (0 ≤ ≤ 0.15, represents the mol % of Mo in the initial solution) red phosphors via co-precipitation method. The doping of Mo not only significantly improve the moisture resistance of the KNbF: Mn phosphor without any passivation and surface coating, but also effectively enhance the luminescence properties and thermal stability. In particular, the obtained KNbMoF: Mn ( = 0.05) phosphor possesses the quantum yield of 47.22% and retains 69.95% of its initial emission intensity at 353 K. Notably, the normalized intensity of the red emission peak (627 nm) for the KNbMoF: Mn ( = 0.05) phosphor is 86.37% of its initial intensity after immersion for 1440 min, prominently higher than that of the KNbF: Mn phosphor. Moreover, a high-performance WLED with high CRI of 88 and low CCT of 3979 K is fabricated by combining blue chip (InGaN), yellow phosphor (YAlO: Ce) and the KNbMoF: Mn ( = 0.05) red phosphor. Our findings convincingly demonstrate that the KNbMoF: Mn phosphors have a good practical application in WLEDs.