Bismuth-Activated Persistent Phosphors

Bismuth cations (e.g., Bi3+, Bi2+) are very promising non-rare-earth activators in persistent luminescence (PersL) materials. Recently, much work has been devoted to modulating the host structures and defects to obtain high-intensity luminescence and/or tunable excitation and emission bands of Bi-activated persistent phosphors. A timely review on Bi-based PersL phosphors would be highly attractive for future materials' design and applications. The present review discusses the recent advances in Bi-activated PersL phosphors with focus on the structure-defect-property relationships. Firstly, the basic ionic configurations of Bi cations as an activator are discussed in detail, followed by the classification as well as elaboration of Bi-activated PersL phosphors according to emission wavelength. Then, the modulation strategies of PersL through adjusting the local structures are highlighted, which include defect engineering and theoretical prediction. These strategies allow for the effective regulation of PersL in Bi-activated phosphors that have extensively been explored in information storage, X-ray imaging, stress sensing, anti-counterfeiting, etc. Finally, future challenges and perspectives toward Bi-activated PersL phosphors are proposed. This review provides solid guidelines of designing diverse PersL materials with tunable properties for various optical applications in the future.