Novel Mn(4+)-Activated K(2)Nb(1−x)Mo(x)F(7) (0 ≤ x ≤ 0.15) Solid Solution Red Phosphors with Superior Moisture Resistance and Good Thermal Stability

Nowadays, Mn(4+)-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 K(2)Nb(1−x)Mo(x)F(7) novel fluoride solid solution system, and synthesized the Mn(4+)-activated K(2)Nb(1−x)Mo(x)F(7) (0 ≤ x ≤ 0.15, x represents the mol % of Mo(6+) in the initial solution) red phosphors via co-precipitation method. The doping of Mo(6+) not only significantly improve the moisture resistance of the K(2)NbF(7): Mn(4+) phosphor without any passivation and surface coating, but also effectively enhance the luminescence properties and thermal stability. In particular, the obtained K(2)Nb(1−x)Mo(x)F(7): Mn(4+) (x = 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 K(2)Nb(1−x)Mo(x)F(7): Mn(4+) (x = 0.05) phosphor is 86.37% of its initial intensity after immersion for 1440 min, prominently higher than that of the K(2)NbF(7): Mn(4+) 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 (Y(3)Al(5)O(12): Ce(3+)) and the K(2)Nb(1−x)Mo(x)F(7): Mn(4+) (x = 0.05) red phosphor. Our findings convincingly demonstrate that the K(2)Nb(1−x)Mo(x)F(7): Mn(4+) phosphors have a good practical application in WLEDs.