LAUSR

Persistent luminescence (PersL) materials containing deep traps have attracted great attention in the field of optical information storage. However, the lack of nanomaterials with satisfactory light storage ability has become one of the main obstacles to the practical applications. In this work, NaMgF3:Tb3+@NaMgF3:Tb3+ nanoparticles are reported which exhibit excellent light storage ability into deep traps upon X‐ray irradiation and controllable photon emissions under thermal stimulation. A surface passivation strategy by constructing a core–shell structure is adopted, which is proved valid to greatly enhance the PersL efficiency. To understand the possible mechanism on the light storage and thermally stimulated PersL in the NaMgF3:Tb3+@NaMgF3 nanoparticles, an energy level diagram is built and the electronic transition processes are clarified. According to the proposed mechanism, the Tb3+ ions possibly serve as both emitting centers and trap centers in the NaMgF3 host during the X‐ray irradiation. Due to the excellent dispersibility and stability in water, luminescent inks containing the nanoparticles are successfully prepared and the applications to inkjet printing optical information storage and information decryption are demonstrated. The developed NaMgF3:Tb3+@NaMgF3 PersL nanoparticles may inspire further research on lanthanide‐activated fluoride PersL nanoparticles and provide new opportunities to the next‐generation information storage and biomedical technologies.