Thermally Stable Narrow-Band Green-Emitting Phosphor MgAl2O4:Mn2+ toward Wide Color Gamut Backlight Display Application
The discovery of stable narrow-band green emitting phosphor suitable for blue InGaN chip excitation is crucial to improve the color gamut of the phosphor converted backlighting device. However, it is a great challenge. Herein, a Mn2+ activated thermally stable narrow-band green emitting phosphor MgAl2O4:Mn2+ peaking at 525 nm with a full-width at half-maximum (FWHM) of 35 nm and quantum efficiency of 45% upon 450 nm blue-light excitation is demonstrated. This phosphor does not exhibit thermal quenching even up to 300 0C (109.5%@ 300 0C of the integrated emission intensity at 23 0C) due to the high rigidity of the host MgAl2O4. Using the as-synthesized optimized phosphor Mg0.95Al2O4:0.05Mn2+ as green light component, and commercial phosphor K2SiF6:Mn4+ as red one, an InGaN chip excited white LED device with a color gamut of 116% National Television System Committee (NTSC) standard is obtained. Furthermore, applying the fabricated LED device for backlights in liquid crystal display (LCD) TV, more colorful frame can be realized as compared to the one used commercial LED backlights, suggesting the Mn2+ ions based green emitting phosphor has high potential for LCD backlights.