Ultra‐Narrowband Green‐Emitting Transparent Composite Ceramics for Laser‐Driven Display

Laser-driven projection displays face a critical challenge in developing laser-excitable and high-performance narrowband green emitters. Herein, new Al₂O₃-LaMgAl₁₁O₁₉: Mn²⁺ (Al₂O₃-LMA: Mn²⁺) transparent composite ceramics are reported via high-temperature vacuum sintering, which produces a high-color-purity (95.4%) green emission with full width at half maximum of 24 nm and superior thermal and moisture and laser irradiation stability. These are attributed to low electron-phonon couple, weak crystal-field effect, an individual lattice location of Mn²⁺ activators in high structural rigid host, and the incorporation of a high-thermal-conductivity Al₂O₃ secondary phase. As a result, the composite ceramics are demonstrated as an attractive color converter with a high external quantum efficiency (38%) and absorption coefficient (53%), which ensures a luminous flux of 2012 lm @40.0 W, a luminous efficacy of 67.7 lm W^-1, and a green light conversion efficiency of 20.3% upon blue laser irradiation. This enables to construct a brand-new laser-driven prototype display with a record color gamut beyond Rec.2020 standard (100.8%), outperforming commercial YAG: Ce³⁺ and β-SiAlON: Eu²⁺. This exploration in ultra-narrowband green luminescent materials is poised to accelerate the development of "ideal displays" for laser-driven projection display technology.