A Novel Ba₂LuNbO₆:Mn⁴⁺Double-Perovskite Far-Red Phosphor for Indoor Plant Cultivation

Far-red light is very important for plant photomorphogenesis. Herein, we report a novel Ba2LuNbO6:Mn4+ far-red phosphor by high temperature solid state method. Its crystal structure and optical property are systematically studied. The as-fabricated Ba2LuNbO6:Mn4+ phosphor exhibits broad excitation bands ranging from 300 to 550 nm, attributed from the d-d transitions of Mn4+, and emits expected far-red light with the center of 698 nm (2Eg → 4A2g) under 370 nm UV irradiation. Furthermore, the temperature-dependent photoluminescence (PL) intensity and the activation energy of Mn4+ are investigated in detail. A far-red pc-LED is fabricated by combining the Ba2LuNbO6:Mn4+ and 365 nm UV chip, showing a good overlap with the absorption data of phytochrome PFR. Surprisingly, by introducing secondary cation ion Gd3+, the far-red PL intensity is obviously enhanced because of crystal field adjusted and nephelauxetic effect. Finally, our work supplies a novel far-red candidate phosphor for indoor plant cultivation.