Warm-white-light emitting diode utilizing a single-phase full-color Ba3MgSi2O8:Eu2+, Mn2+ phosphor

The Ba3MgSi2O8:Eu2+, Mn2+ shows three emission colors: 442, 505, and 620 nm. The 442 and 505 nm emission originate from Eu2+ ions, while the 620 nm emission originates from Mn2+ ions. The excitation bands of three emission colors are positioned around 375 nm. Electron paramagnetic resonance measurement demonstrates that Eu2+ ions are occupied with three different Ba2+ sites. The red emission of Mn2+ ions has a long decay time of 750 ms due to persistent energy transfer from oxygen vacancies to Mn2+ ions, while the blue and green bands of Eu2+ ions have decay times of 0.32 and 0.64 mus, respectively. The fabricated white-light emitting diode using a 400-nm-emissive chip with a white-light emitting Ba3MgSi2O8:Eu2+, Mn2+ phosphor shows warm white light and higher color stability against input power in comparison with a commercial GaN-pumped (Y1-xGdx)(3)(Al1-yGay)(5)O-12:Ce3+ phosphor. (C) 2004 American Institute of Physics.