High luminescence intensity and long persistent duration is desired for practical application of long persistent materials. But it still remains challenging due to insufficient phosphors to meet the commercial request and a general lack of understanding of luminescence mechanism. In this work, green persistent luminescent phosphor Zn 2 SiO 4 :Mn 2+ ,Pr 3+ was first synthesized by traditional solid-state reaction method with self-made SiO 2 submicrospheres as silicon source. The morphology, crystal structure, photoluminescence and the long afterglow performance have been investigated systematically. Interestingly, the longest persistent luminescence is observed for 0.025 Mn 2+ , 0.001 Pr 3+ co-doped Zn 2 SiO 4 with a persistent time of ∼2640 s at (0.32 mcd/m 2 ), which is 20 times longer than those of Zn 2 SiO 4 host or single Mn 2+ doped Zn 2 SiO 4 phosphors. The possible persistent mechanism has been discussed. The finding will be beneficial for developing persistent phosphors with superior functionalities.
Dynamic time-dependent afterglow materials have shown good application potential in the field of anti-counterfeiting. However, their short decay time (<10 s) causes poor concealment and limits their application expansion. In this work, multiple afterglow emission centers with different decay rates have been produced in stable zinc silicate glass ceramics by phase transformation through a heat-treatment method, causing an effective long-lasting (>600 s) time-dependent afterglow that is tunable from orange/yellow to red. Mechanism analysis suggested that this is related to the varied substitution tendency of alkali metal ions into different phases (α,β-Zn2SiO4), leading to different depths of oxygen vacancies, which are favorable for room-temperature afterglow. Finally, we propose a novel anti-counterfeiting encryption strategy that can return different information by changing the observation frequency.
Photo-stimulated luminescent materials are one of the most attractive alternatives for next-generation optical information storage technologies. However, there are still some challenges in regulating appropriate energy levels of traps in luminescent materials for optical information storage. Herein, a green emission nanophosphor Zn 2 SiO 4 : Mn 2+ , Cr 3+ with the trap depth of 1.05 eV, fulfilling the requirements for optical information storage, was fabricated for the first time through the solution combustion method and subsequent heat treatment at 1000 °C for 2 h. The crystal structure, micromorphology , photoluminescence (PL), photoluminescence excitation (PLE), and afterglow properties of Zn 2 SiO 4 : Mn 2+ , Cr 3+ were studied systematically. By applying the strategy of trap depth engineering, high trap density with proper trap depth was observed when Cr 3+ ions were introduced into Zn 2 SiO 4 : Mn 2+ . Thermoluminescence (TL) glow-curve analysis through the initial rise (IR) method was conducted to gain some insights into the information of traps. As proof of application, optical information storage was experimentally achieved by choosing 275 nm illumination for “information writing” and 980 nm NIR excitation for “information reading”. The results indicate that Zn 2 SiO 4 : Mn 2+ , Cr 3+ phosphor holds promise for potential applications in the field of optical information storage.
危险品化学品经营许可证（带存储）