Thermally Stable Red-Emitting Ca 18 K 3 Sc(PO 4 ) 14 :Mn 2 + Phosphor and Enhanced Luminescence by Energy Transfer Between Ce 3 + -Eu 2 + -Mn 2 .

It is significant and valuable to investigate novel and high-performance red-emitting phosphors for high-quality wLED applications. Based on this consideration, we developed a novel Mn 2+ -doped red Ca 18 K 3 Sc(PO 4 ) 14 :Mn 2+ (CKSP:Mn 2+ ) phosphor. The emission peak of CKSP:Mn 2+ is located at 640 nm, presenting a broadband red emission with a fwhm of 79 nm under 405 nm excitation. The CKSP:1.0Mn 2+ phosphor shows superior thermal stability. At 150 °C, the integrated PL intensity and peak intensity of the CKSP:1.0Mn 2+ phosphor maintain 93.2 and 85.7% of those at 25 °C, respectively. Through the strategy of energy transfer among Ce 3+ -Eu 2+ -Mn 2+ , the PL intensity of Mn 2+ has increased by nearly 118 times, and the quantum yield has improved from 6 up to 72%. The structure-related photoluminescence and energy transfer mechanisms are discussed in detail. The as-fabricated wLED pumped by a 370 nm LED chip combining commercial the green (Sr,Ba) 2 SiO 4 :Eu 2+ phosphor, blue BaMgAl 10 O 17 :Eu 2+ phosphor, and the as-synthesized CKSP:1.0Mn 2+ , 0.02Eu 2+ , 0.40Ce 3+ phosphor shows excellent color quality (CCT = 5555 K, Ra = 87), which indicates that the CKSP:1.0Mn 2+ , 0.02Eu 2+ , 0.40Ce 3+ phosphor has extraordinary broad prospects in future wLED applications.