Anomalous 5D0→7F4 Transition of Eu3+‐Doped BaLaGaO4 Phosphors for WLEDs and Plant Growth Applications

Abstract Europium (Eu 3+ ) doped phosphors typically exhibit orange or red emission and are used in lighting and display applications, originating from the 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 transitions of Eu 3+ . However, BaLaGaO 4 : x Eu 3+ deep‐red phosphor, when excited by near‐ultraviolet light, is mainly 5 D 0 → 7 F 4 transition (703 nm). Meantime, the BaLaGaO 4 : 0.30Eu 3+ exhibits a high I 423K /I 298K value of 71% and a high quantum yield of 82.54%. Furthermore, the prepared samples are mixed with commercial blue and green phosphors in a certain proportion to make white light‐emitting diodes (WLEDs). The color coordinate of the fabricated WLEDs is (0.3208, 0.3436), with a color rendering index of 91.9 and an R9 value of 73. Based on the unique spectral characteristics of this compound, a prototype device of a deep‐red LED with phosphor conversion is developed, which exhibits color coordinates (0.6294, 0.3581) and a color purity of 96.4%. The conducted germination experiments with plant seeds have provided compelling evidence regarding the considerable positive effects of the deep‐red LEDs on plant growth. These findings further emphasize the highly promising potential application of BaLaGaO 4 : Eu 3+ deep‐red phosphor in WLEDs and plant growth lighting.