Anomalous ⁵D₀⁷F₄ Transition of Eu³⁺-Doped BaLaGaO₄ Phosphors for WLEDs and Plant Growth Applications

Europium (Eu3+) doped phosphors typically exhibit orange or red emission and are used in lighting and display applications, originating from the D-5(0)-> F-7(1) and D-5(0)-> F-7(2) transitions of Eu3+. However, BaLaGaO4: xEu(3+) deep-red phosphor, when excited by near-ultraviolet light, is mainly D-5(0)-> F-7(4) transition (703 nm). Meantime, the BaLaGaO4: 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 BaLaGaO4: Eu3+ deep-red phosphor in WLEDs and plant growth lighting.