Enhanced persistent luminescence of MgGa2O4:Cr3+ near-infrared phosphors by codoping Nb5+

Near-infrared (NIR) long persistent phosphors have potential applications in medical imaging, anti-counterfeiting signs, and night vision surveillance. It is very important to obtain NIR long persistent phosphors with bright intensity and longer persistent time. In this article, Nb5+ ions are introduced into the NIR phosphor MgGa2O4: Cr3+ and the luminescence properties are investigated. The phosphors exhibit NIR long persistent emission peaking at 706 nm. After codoping with Nb5+, the afterglow intensity is increased 4 times and the photoluminescence (PL) intensity is improved 2.34 times. Thermoluminescence tests demonstrate that the trap density can be enriched and the distribution of traps has been adjusted via codoping Nb5+. Therefore co-doping Nb5+ can significantly improve the afterglow performance. This article might provide reference for designing new near-infrared long persistent phosphors.