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

Discovering new Eu 2+ ‐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 Sr 2 Sc 0.5 Ga 1.5 O 5 :Eu 2+ 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 Eu 2+ ions tend to enter the [Sc1/Ga1O 6 ] and [Ga2O 6 ] polyhedrons with small coordination numbers, leading to the broadband red emission originated from large crystal field splitting of Eu 2+ 5 d 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 SrBaSc 0.5 Ga 1.5 O 5 :Eu 2+ . The WLED device fabricated by blending the red Sr 1.7 Ba 0.3 Sc 0.5 Ga 1.5 O 5 :Eu 2+ and yellow Y 3 (Al, Ga) 5 O 12 :Ce 3+ phosphors shows a high color‐rendering index ( R a = 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 Eu 2+ ‐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.