Rapid Synthesis of Red-Emitting Sr2Sc0.5Ga1.5O5:Eu2+ Phosphors and the Tunable Photoluminescence Via Sr/Ba Substitution

Zhiyu Yang, Yayun Zhou, Jianwei Qiao, Maxim S. Molokeev, Zhiguo Xia. ADVANCED OPTICAL MATERIALS https://doi.org/10.1002/adom.202100131

Discovering new Eu2+-doped red-emitting phosphors in oxide-based materials is a challenge for white light-emitting diode (WLED) applications. Herein, a highly efficient high-frequency induction heating method is employed to rapidly prepare the red-emitting Sr2Sc0.5Ga1.5O5:Eu2+ phosphors peaking at 614 nm and exhibiting a high photoluminescence quantum yield of 78.4% under the excitation of 440 nm. The structural and spectral analyses suggest that Eu2+ ions tend to enter the [Sc1/Ga1O6] and [Ga2O6] polyhedrons with small coordination numbers, leading to the broadband red emission originated from large crystal field splitting of Eu2+ 5d level. The chemical substitution of Ba in the Sr site enhances the thermal stability and helps to the photoluminescence tuning from 614 to 728 nm in SrBaSc0.5Ga1.5O5:Eu2+. The WLED device fabricated by blending the red Sr1.7Ba0.3Sc0.5Ga1.5O5:Eu2+ and yellow Y3(Al, Ga)5O12:Ce3+ phosphors shows a high color-rendering index (Ra = 91.1), and low color-correlated temperature (CCT = 4750 K). This study aims to provide a new synthesis method and design principle for guiding the development of Eu2+-doped oxide-based red phosphors with low preparation cost; moreover, the photoluminescence tuning strategy via cation substitutions is essential to achieve tunable emission, even the near-infrared luminescence.