A novel far-red and near-infrared adjustable phosphor Sr₉Al(PO₄)₇:Cr³⁺: structure and luminescence properties

Novel Cr³⁺-doped Sr₉Al(PO₄)₇ phosphors were successfully synthesized by high-temperature solid-state method. The result of XRD characterization indicates that Cr³⁺ ions are doped successfully into the lattice. Under the excitation at 397 nm, the samples emit far-red light from 690 to 697 nm with central peak at 693 nm because of the ²E→⁴A₂ spin-forbidden transition of Cr³⁺. And under the excitation at 467 nm, the samples emit NIR light from 740 to 860 nm with central peak at 817 nm because of the ⁴T₂→⁴A₂ spin-allowed transition of Cr³⁺. The research results of this paper indicate that Cr³⁺-doped Sr₉Al(PO₄)₇ phosphors can make a great contribution to the field of infrared illumination and indoor plant cultivation.