Efficient and Thermally Stable Cr3+‐Doped Phosphor Achieved by Cation Substitution: Plant Lighting Application

Abstract Far‐red phosphor‐converted light‐emitting diodes are receiving increasing attention as an essential component of the next‐generation plant‐growth lights. However, developing far‐red phosphors with high quantum efficiency, low thermal quenching, and suitable emitting wavelength is crucial and urgent. Herein, a new far‐red phosphor BaY 2 Ga 3.9 GeO 12 :0.1Cr 3+ with high internal quantum efficiency (98%) and thermal stability (90.2%@423K) is obtained via the substitution of CaO 8 with bigger BaO 8 dodecahedrons, which is attributed to variations in the lattice environment of Cr 3+ . Meanwhile, controllable emission tuning from 780 to 708 nm and enhanced luminescence performance are achieved due to the cation substitution can reduce the production of Cr 4+ and modulate the lattice occupancy of the Cr 3+ ions, and the enhancement of metal‐ligand interactions resulting in the enhancement of the crystal field and the breaking of the forbidden d‐d transition of Cr 3+ . The proof‐of‐concept demonstration of the pakchoi lighting experiment reveals the great potential of BaY 2 Ga 3.9 GeO 12 :Cr 3+ phosphor in stimulating plant growth and pushing the yield. These results demonstrate the feasibility of cationic substitution to optimize the optical performance of Cr 3+ ‐doped phosphors, providing an alternative strategy for designing efficient far‐red light sources for plant lighting.