X-ray-Excited Super-Long Green Persistent Luminescence from Tb3+ Monodoped β-NaYF4

Here, an X-ray-excited super-long afterglow phosphor β-NaYF4:Tb3+ has been discovered for the first time. After X-ray irradiation, the green emission can persist for more than 240 h. After 120 h, the power density of afterglow reached 3.76 × 10–6 W·m–2, which can be clearly observed by the naked eye under dark vision. Also, combined with the results of thermoluminescence and photoluminescence, the super-long afterglow emission of β-NaYF4:Tb3+ can be ascribed to the tunneling model associated with F centers. More importantly, the super-long green afterglow emission of β-NaYF4:Tb3+ has been successfully used as an in vivo light source to activate g-C3N4 for photodynamic therapy and bacteria destruction. Furthermore, super-long persistent luminescence of β-NaYF4:Tb3+ could be repeatedly charged by X-rays for many cycles, which indicates that the phosphors have high photostability under repeated cycles of alternating X-ray irradiation.