LAUSR

It is extremely necessary to develop LEDs with a high color index for many special applications. In this study, novel single-phase warm white light-emitting 3/2-mullite (Al6Si2O13):Eu2+,Mn2+ phosphors were prepared via the high-temperature solid-state reaction method. The emission hue can be precisely controlled from (0.2496, 0.3032) to (0.4001, 0.3031) by altering the Eu2+/Mn2+ ratio via the energy transfer route, where warm-white emissions with CIE coordinates of (0.3440, 0.3302) are achieved using UV-excited Al6Si2O13:2.0%Eu2+,0.6%Mn2+ phosphors. The energy transfer between Eu2+ and Mn2+ in the Al6Si2O13 host is demonstrated to be a nonradiative dipole–dipole interaction. A warm-white LED device comprising the Al6Si2O13:2.0%Eu2+,0.6%Mn2+ phosphor and an NUV (365 nm) chip operated at 120 mA yields white-light emissions with a correlated color temperature of 5656 K and color coordinates of (0.3289, 0.3413). Moreover, it should be noted that the color rendering indices of Ra and R9 can reach up to 92.4 and 97.0, respectively. Our proposed Al6Si2O13:2.0%Eu2+,0.6%Mn2+ phosphor with high color rendering index has good application prospects.