Synthesis and luminescence properties of Ca2AlNbO6:Fe3+ phosphor for plant growth lighting

With the development of plant growth lighting, more and more attention has been paid to red and far red luminescent materials. In this work, we synthesize successfully a non-rare earth and non-toxic Ca 2 AlNbO 6 :Fe 3+ phosphor in air and investigate the crystal structure, morphology, and luminescence properties of Ca 2 AlNbO 6 :Fe 3+ by using powder X-Ray Diffraction, the field emission scanning electron microscopy, and the Edinburgh steady-state FS5 spectrometer, respectively. The far-red emission with peak at 714 nm of Ca 2 AlNbO 6 :Fe 3+ is due to the 4 T 1 ( 4 G) → 6 A 1 ( 6 S) transition of Fe 3+ ion. Photoluminescence excitation (PLE) spectrum of Ca 2 AlNbO 6 :Fe 3+ includes four PLE peaks, which are assigned to the O 2− → Fe 3+ charge transfer band (CTB) (309 nm), the 6 A 1 ( 6 S) → 4 T 1 ( 4 P) (364 nm), 6 A 1 ( 6 S) → 4 E( 4 D) (395 nm), and 6 A 1 ( 6 S) → 4 T 2 ( 4 G) (532 nm) transitions of Fe 3+ , respectively. We further study the concentration/temperature dependent emission spectra and time-resolved emission spectra. The optimal Fe 3+ doping concentration (0.6mol%) and the only luminous center (Fe 3+ ) in Ca 2 AlNbO 6 :Fe 3+ are confirmed. The decay curves of Ca 2 AlNbO 6 :xFe 3+ (0.2 mol% ≤ x ≤ 1.2 mol%) are measured and their lifetimes decrease from 463.24 to 385.29 μs＀ The emission spectra under different temperatures prove that Ca 2 AlNbO 6 :Fe 3+ has a good heat stability. We explain the luminous mechanism and concentration/thermal quenching mechanisms, and further research the application prospect of Ca 2 AlNbO 6 :Fe 3+ in plant growth lighting.