Luminous characteristics and thermal stability of BaMgAl10O17:Eu2+ phosphor for white light-emitting diodes

A blue-emitting phosphor, BaMgAl10O17:Eu2+ (BAM) was prepared by the solid-state reaction and X-ray powder diffraction (XRD) analysis confirmed the formation of BAM. Photoluminescence (PL) results showed that the phosphor can be efficiently excited by the light from near ultraviolet (NUV) to visible, and exhibited bright blue emission. The effect of the doped-Eu2+ in BAM on the PL was investigated. To improve the BAM's thermal stability, BAM doped with additional Mg2+ was studied. The experiment results showed that additional 0.05 mol Mg2+-doped BAM had the highest emission intensity and thermal stability. By combining with NUV LED chip (GaN-based 380 nm emitting), a novel intense white LED was fabricated based on the blue phosphor BAM and a red phosphor Ca(La0.5Eu0.5)4Si3O13. The white LED has the characteristics of color-rendering index of 87, CIE chromaticity coordinates (x, y) of (0.3225, 0.3187), color temperature Tc of 5680 K, and light output of 51.7 lm/W under the forward-bias current of 20 mA. As the current increases, the relative intensity increases, the correlated color temperature Tc increases from 4000 to 7900 K and the color-rendering index Ra increases from 83 to 91 simultaneously.