A thermally stable narrow-band green-emitting phosphor MgAl2O4:Mn2+ for wide color gamut backlight display application

摘要

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 a quantum efficiency of 45% upon 450 nm blue-light excitation is demonstrated. This phosphor does not exhibit thermal quenching even up to 300 degrees C (109.5%@300 degrees C of the integrated emission intensity at 23 degrees C) due to the high rigidity of the host MgAl2O4. Using the as-synthesized optimized phosphor Mg0.95Al2O4:0.05Mn(2+) as the green light component, and a commercial phosphor K2SiF6:Mn4+ as the red one, an InGaN chip excited white LED device with a color gamut of 116% National Television System Committee (NTSC) standard is obtained. Furthermore, by applying the fabricated LED device for backlights in a liquid crystal display (LCD) TV, a more colorful frame can be realized compared to when commercial LED backlights are used, suggesting that the Mn2+ ion based green emitting phosphor has great potential for application as LCD backlights.