Glass crystallization making red phosphor for high-power warm white lighting

Rapid development of solid-state lighting technology requires new materials with highly efficient and stable luminescence, and especially relies on blue light pumped red phosphors for improved light quality. Herein, we discovered an unprecedented red-emitting Mg₂Al₄Si₅O₁₈:Eu²⁺ composite phosphor (λ_ex = 450 nm, λ_em = 620 nm) via the crystallization of MgO-Al₂O₃-SiO₂ aluminosilicate glass. Combined experimental measurement and first-principles calculations verify that Eu²⁺ dopants insert at the vacant channel of Mg₂Al₄Si₅O₁₈ crystal with six-fold coordination responsible for the peculiar red emission. Importantly, the resulting phosphor exhibits high internal/external quantum efficiency of 94.5/70.6%, and stable emission against thermal quenching, which reaches industry production. The maximum luminous flux and luminous efficiency of the constructed laser driven red emitting device reaches as high as 274 lm and 54 lm W^-1, respectively. The combinations of extraordinary optical properties coupled with economically favorable and innovative preparation method indicate, that the Mg₂Al₄Si₅O₁₈:Eu²⁺ composite phosphor will provide a significant step towards the development of high-power solid-state lighting.