Near‐Infrared Persistent Luminescence and Trap Reshuffling in Mn⁴⁺ Doped Alkali‐Earth Metal Tungstates

Abstract Near‐infrared persistent luminescent materials have great potential for in vivo bioimaging and night‐vision surveillance due to their long‐lasting autofluorescence‐free emission through deep tissues and multicycle photostimulated luminescence by releasing energy from captured traps using high‐intensity 808 or 980 nm lasers. However, phosphors combining both near‐infrared persistent luminescence and photostimulated luminescence are found mostly in chromium doped gallates hosts, other emitters are rarely reported. Herein, a new material system with near‐infrared persistent luminescence is achieved in tetravalent manganese doped double‐perovskite alkali‐earth metal tungstates via the aliovalent substitution of calcium ions with lanthanum ions. Persistent luminescence can be generated via X‐ray irradiation, providing great promise in long‐term deep‐tissue ultrasensitive imaging, information storage, and X‐ray detection. Photostimulated detrapping is successfully demonstrated using a common 420 nm light emitting diode instead of a high‐intensity 808 or 980 nm laser. The traps distribution is proved to be reshuffled upon this laser‐free visible light stimulation. Reshuffling of trap distributions upon visible light stimulation may be promising for optical information storage applications. This work is expected to broaden the range of near‐infrared persistent material systems and provides new insights into manipulating photostimulated traps via laser‐free light stimulation.