CALSON:Ce³⁺ Phosphor Ceramics for Laser‐Driven Solid‐State Lighting

Laser‐driven solid‐state lighting is recognized as next‐generation high‐power and super‐brightness lighting sources, but the color temperature of which is greatly limited by scarcity of efficient orange–red color converters. To address this issue, a thermally robust phosphor ceramic of Ca 1‐ x ‐ y Li x Al 1‐ x ‐ y Si 1+ x + y N 3‐ y O y :Ce 3+ (CALSON:Ce is reported, with chromatic coordinates of x = 0.15 and y = 0.1) prepared by spark plasma sintering. Highly efficient CALSON:Ce phosphor powders are first synthesized by “seed” sintering and further treated by acid washing, demonstrating an external quantum efficiency (EQE) as high as 66% and a photoluminescence retention of 91% at 200 °C. The phosphor ceramic fabricated at 1600 °C has the highest EQE of 57% and luminous saturation threshold of 19.58 W mm −2 . By coating the CALSON:Ce ceramic with a La 3 Si 6 N 11 :Ce (LSN:Ce) phosphor layer, white light can be generated under blue laser excitation with a power density of 11.28 W mm −2 , achieving a color temperature of 4943 K, a luminous flux of 675.76 lm, and a luminous efficacy of 119.81 lm W −1 . This work proposes a “seed” sintering method that enables to improve the quantum efficiency of phosphors and ceramics.