Competitive Site Occupation toward Improved Quantum Efficiency of SrLaScO4:Eu Red Phosphors for Warm White LEDs

作者：Zhiyu Yang, Gaochao liu, Yifei Zhao, Yayun Zhou, Jianwei Qiao, M. Molokeev, H. Swart, Z. Xia · 发表于：Advanced Optical Materials · 年份：2022 · DOI：10.1002/adom.202102373 · 被引用次数：85

The discovery of Eu2+‐doped high‐efficiency red phosphors remains a vital challenge for white light‐emitting diode (WLED) applications. It is therefore urgent to find effective strategies managing the oxidation state to help reduce Eu3+ to Eu2+ and accordingly increase the photoluminescence quantum yield (PLQY). Herein, a new red‐emitting SrLaScO4:Eu phosphor is designed, and the PLQY is enhanced from 13% to 67% under 450 nm excitation by employing (NH4)2SO4‐assisted sintering. Combined structural analysis, optical spectroscopy, and theoretical calculation reveal that predominant Eu2+ prefers to occupy the Sr2+ sites in the SrLaScO4 enabling red emission, and a competitive site occupation of Eu3+ in La3+ can be restrained, and the reduction mechanism of Eu3+ to Eu2+ originating from the (NH4)2SO4 addition is analyzed. The fabricated WLED device using red‐emitting SrLaScO4:Eu and yellow‐emitting Y3(Al,Ga)5O12:Ce3+ exhibits a high color‐rendering index of 86.7 at a low correlated color temperature of 4005 K. This work provides a feasible reduction strategy for guiding the development of high‐efficiency Eu2+‐doped red phosphor for WLED applications.