A novel efficient Mn4+-activated Ba2YTaO6 far-red emitting phosphor for plant cultivation LEDs: Preparation and photoluminescence properties

Novel efficient Ba 2 YTaO 6 :Mn 4+ (BYT:Mn 4+ ) far-red emitting double-perovskite phosphors for plant cultivation LEDs were reported in this article. These phosphors were successfully synthesized via a traditional high-temperature solid-state reaction method, and their crystal structure, luminescence properties, fluorescence decay lifetimes, Commission Internationale de l'Eclairage (CIE) chromaticity coordinates, internal quantum efficiency, and thermal stability have been systematically investigated. XRD Rietveld refinement demonstrated that the BYT:Mn 4+ compound crystallized into cubic crystal system with Fm 3 ‾ m space group, and the lattice parameter were a  =  b  =  c  = 8.445 (7) Å, α  =  β  =  γ  = 90°, and V  = 602.231 (10) Å 3 . Interestingly, the obtained samples showed an intense far-red emission band centered at 690 nm under excitation of 360 nm, which matched well with the absorption band of phytochrome P FR. In BYT:Mn 4+ phosphors, the Mn 4+ ions occupied the TaO 6 octahedron by replacing the Ta 5+ site, and the optimal doping concentration of Mn 4+ ions was determined to be 0.4 mol%. The CIE chromaticity coordinates and internal quantum efficiency of BYT:0.4%Mn 4+ phosphors were (0.7283, 0.2717) and 41.5%, respectively. In addition, when the temperature reached at 423 K, the emission intensity of BYT:0.4%Mn 4+ phosphors remained 37% of that at 303 K. Therefore, all of these investigations demonstrated that BYT:Mn 4+ phosphors could be used as potential far-red emitting phosphors for plants cultivation LEDs.