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. • New non-rare earth and non-toxic Ca 2 AlNbO 6 :Fe 3+ are successfully synthesized in air. • PLE spectrum with two broad bands peaking at 364 and 532 nm is observed. • Ca 2 AlNbO 6 :Fe 3+ emits far-red emission owing to the 4 T 1 ( 4 G) .→ 6 A 1 ( 6 S) transition of Fe 3+ ion. • PL spectrum of Ca 2 AlNbO 6 :Fe 3+ matches with Pr and Pfr absorption spectra of plant.