Cr³⁺:SrGa₁₂O₁₉: a broadband near-infrared long-persistent phosphor

Cr(3+)-doped SrGa12O19 is demonstrated to be a broadband near-infrared (650-950 nm) long-persistent phosphor whose luminescence can last for more than 2 h after ultraviolet irradiation is stopped. Detailed analysis of the photoluminescence and thermoluminescence spectra and of the persistent decay behavior of the Cr(3+)-doped SrGa12O19 samples indicate that the persistent energy transfer from the SrGa12O19 host to the Cr(3+) ions and the filling and release of electrons into and from the shallow and deep traps through the conduction band is responsible for the long-persistent phosphorescence.