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 (λex = 450 nm, λem = 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.