Dual‑substitution strategy for highly efficient Far‑red Mn4+‑doped double perovskite phosphors toward plant growth lighting

Far-red phosphors have garnered significant research interest due to their essential function in plant growth lighting. Nevertheless, the development of plant lighting technologies is constrained by the relatively low efficiency and inadequate thermal stability of oxide‑based deep-red-emitting phosphors. In this work, we synthesize the far-red Mn 4+ -doped double perovskite-structured oxides Ba 2 MgWO 6 (BMWO: Mn 4+ ) by the high-temperature solid-state method and enhance its luminescence through dual-substitution strategy. By substituting Mg 2+ with Gd 3+ and Ca 2+ , the emission intensity of BMWO: Mn 4+ has been increased from the initial 100 to 425 and 3716%, respectively, while the quantum yield improves from 0.2 to 89.9%. Meanwhile, BaCa 0.9 Gd 0.1 WO 6 : Mn 4+ (BC 0.9 G 0.1 WO: Mn 4+ ) also possesses excellent thermal stability, retaining 78.2% of its initial intensity at 423 K. Based on crystal structure analysis and electron cloud characterization, we found that the enhancement of Mn 4+ luminescence originates from the modulated crystal field environment of Mn 4+ , which affects the lattice symmetry of the [WO 6 ] octahedra as well as the vibrational stretching modes. Finally, the pc-LEDs based on BC 0.9 G 0.1 WO: Mn 4+ exhibits strong overlap with the plant phytochromes P R /P FR . This work offers both a strategy for tuning Mn 4+ emission and a practical example for designing artificial lighting systems in plant cultivation.