(INVITED)Broadband emission of Lu2SrAl4SiO12:Eu2+ phosphor for full-spectrum lighting

Single-component broadband white-emitting phosphor is essential in next-generation white light-emitting diodes (WLEDs) devices for full-spectrum lighting applications. Herein, we report an ultra-broadband emitting Lu2SrAl4SiO12:Eu2+ phosphor with the full width at half maximum (FWHM) of ∼245–260 nm. Detailed analysis of the broadband emission mechanism reveals that it consists of two emission bands originating from Eu2+: one is the normal 4f65d1 →4f7(8S7/2) transition, and another is related with Eu2+-Eu3+ intervalence charge transfer (IVCT) emission with bandwidth of 210 nm. Moreover, the broad IVCT emission can be also suppressed by Be2+ doping, forming a narrow-band emission with FWHM = ∼75 nm. A warm WLED with a low correlated color temperature (CCT) of 3373 K and high CIR (Ra) of 85.7 is obtained by coating the broadband Lu2SrAl4SiO12:Eu2+ phosphor on an UV pumping LED, implying its application in full-spectrum warm white lighting.