Multifunctional applications based on the anomalous ⁵D₀ → ⁷F₄ transition in SrGa₄O₇: Eu³

Europium (Eu³⁺)-doped phosphors, widely used in lighting and displays due to orange/red emissions from ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions, face inherent limitations such as low efficiency and weak ⁵D₀ → ⁷F₄ transitions, hindering far-red emission. This study presents SrGa₄O₇: 0.3Eu³⁺ (SGO: 0.3Eu³⁺) deep-red phosphors that overcome these constraints by dominantly utilizing the ⁵D₀ → ⁷F₄ transition (701 nm) under near-UV excitation. The optimized SGO: 0.3Eu³⁺ exhibits exceptional thermal stability, retaining 76 % (393 nm) and 79 % (464 nm) of its room-temperature (300K) emission intensity at 425 K. This phosphor delivers an impressive Quantum yield (QY) of 31.95 % when excited at 393 nm. When integrated with standard blue and green phosphors, the resulting white light-emitting diode (WLED) produces a spectrum ideally suited for plant cultivation. The WLED achieves precise color metrics-with chromaticity coordinates at (0.3669, 0.3848), an excellent color rendering index (CRI) of 91.9, and Correlated Color Temperature (CCT) of 4432 K. Additionally, the deep-red LED prototype, featuring coordinates of (0.6294, 0.3581) and an outstanding 96.4 % color purity, proves highly effective for stimulating plant growth. These results highlight SGO: 0.3Eu³⁺ as an outstanding red-emitting candidate for plant lighting, offering efficient and high-quality solutions for modern agricultural facilities. Its superior optical properties also suggest potential applications in fingerprint detection, anti-counterfeiting ink and related fields.