Na5Gd(MoO4)4: Sm3+ - A red molybdate phosphor with exceptional thermal stability for plant growth lighting

Na5Gd1- x(MoO4)4:xSm3+ (x = 0-0.12) phosphors were synthesized via a high-temperature solid-state technique. Comprehensive analysis was performed on the phase purity, crystal structure, luminescence behavior, and thermal stability of the phosphors. Under excitation at 405 nm, due to the 4G5/2-6Hi (i = 5/2, 7/2, 9/2, and 11/2) transitions of Sm3+ ions, the phosphors emit relatively intense red light. Remarkably, at 150 degrees C, the integrated emission intensity of Na5Gd0.92(MoO4)4:0.08Sm3+ attains 96 % of its value at ambient temperature, demonstrating its excellent thermal stability. A LED light source is created using a commercial 405 nm LED chip and Na5Gd0.92(MoO4)4:0.08Sm3+ phosphor, emitting a vibrant red light. Its electroluminescence spectrum overlaps with the absorption peaks of plant chlorophyll a/b and the phytochrome PR/PFR spectra, indicating its potential for use in plant growth lighting applications.