Color-tunable persistent luminescence in oxyfluoride glass and glass ceramic containing Mn2+:α-Zn2SiO4 nanocrystals

Compared to the conventional opaque persistent luminescence (PersL) materials, transparent PersL glass and glass ceramic are highly desired for night-vision illumination and indication applications. Herein, we report a new transparent oxyfluoride glass and glass ceramic with multi-color persistent luminescence lasting for ∼1 h visible by the naked eye. By adjusting the crystallization duration, controlled growth of 5–20 nm α-Zn2SiO4 nanocrystals in a glass matrix is achieved. Evidently, the coordination environment of Mn2+ evolves from octahedra in the glass host to tetrahedra in the α-Zn2SiO4 nanophase, resulting in the PersL color changing from red to yellow, and then to green, as the crystallization of Mn2+:α-Zn2SiO4 proceeds. The trap statuses in the glass and glass ceramic are studied in detail aided by EPR and TL measurements, demonstrating that the trapped holes with a trap depth distribution of 0.099–0.789 eV for the glass, and 0.094–0.631 eV for the glass ceramic, determine the PersL behaviors. It is noteworthy that this is the first report that oxyfluoride glass and glass ceramic serve as efficient PersL hosts.