Phosphors are efficient luminescent materials that are being extensively used in lighting and displays in today's world.

An intriguing mechanics-induced triple-mode anticounterfeiting device and a moving tactile sensor were developed by simultaneously utilizing transient and persistent mechanoluminescence.

The development of luminescent materials for anticounterfeiting and encryption is of great importance. Herein, we develop a multistimuli-responsive luminescent material, NaCaGeO:Pb/Er, and use it to print luminescent images. The photoluminescence and upconversion luminescence of these images show different patterns and colors under different stimuli. The photostimulated luminescence (PSL) of the printed images causes dynamic changes in appearance and is accordingly applied for dynamic multimodal anticounterfeiting on banknotes. The PSL of these luminescent images is also applied in a virtual war scenario to demonstrate that the dynamic PSL-encrypted information in the fabricated image is sufficiently safe even in extreme cases and that spies will be detected. These results can inspire us with more creative security designs based on this luminescent material.

Anticounterfeiting is a vitally important issue in modern society. At present, the most commonly used luminescent anticounterfeiting technique is based on static photoluminescence (PL), which is easily counterfeited by certain substitutes. In this work, we report for the first time a dynamic PL material, Na2CaGe2O6:Tb3+. Irradiated by a portable ultraviolet (254 nm) lamp, the PL color of the material due to Tb3+ changes from the initial red to yellow and, finally, green. The investigation reveals that the dynamic PL is due to the presence of appropriate traps and the cross-relaxation effect of Tb3+ in Na2CaGe2O6. By employing this unique dynamic PL material, high-level dynamic luminescent anticounterfeiting and encryption devices can be fabricated. The dynamic PL features of the devices are easily detected using a cheap portable lamp, and at present, it is impossible for the features to be faked by any substitutes. In a virtual military scenario, the results demonstrate that the encryption device is safe and that a spy will be detected. Accordingly, this dynamic PL material could inspire more ingenious security designs.

The distinctive crystal characteristics of undoped LiGa5O8 allow the production of abundant defects and traps in the structure, contributing to attractive luminescent properties. In this work, the mechanoluminescent pathways of LiGa5O8 are demonstrated in terms of the defect induced localized energy levels and trap levels, which are further optimized by adjusting the synthesis atmosphere. The results suggest that the LiGa5O8 synthesized under a reducing atmosphere exhibits an extremely intense mechanoluminescence, which is even better than that of commercial ZnS:Cu. Because of the existence of shallow trap with the spontaneous transfer activity at room temperature, the mechanoluminescence of LiGa5O8 can also exhibit a persistent behavior, overcoming the transient emitting problem in most of the previous mechanoluminescent materials. In addition, the mechanoluminescence of LiGa5O8 can be easily and quickly recovered by refilling the energy in traps. As a result, the undoped LiGa5O8 is confirmed to be an efficient material with intense, persistent, and recoverable mechanoluminescence, which is promising to substitute the doped ones for various applications.

With the rapid development of technology, information security has always been considered a major challenge. In this work, the excellent combination of persistent luminescence, photoluminescence, up-conversion luminescence, and thermoluminescence in a particular material Zn 4 B 6 O 13 :Tb 3+ ,Yb 3+ synthesized via a solid-state reaction is reported, which can be used for the information encryption and anti-counterfeiting. Tb 3+ ions were chosen as the emitting centers for multimodal emissions, and Yb 3+ codoping can be used as electron traps and sensitizer to adjust trap distribution and efficient up-conversion luminescence in rareearth-doped luminescent materials. Besides, the as-prepared luminescent materials exhibit high thermal stability and excellent water resistance. On the basis of these properties, the samples were used to print luminescent images through a screen printing process on the film and banknote. The luminescent image in a film is showing different patterns and on a banknote is showing green emissions under different stimulations. These multimodal emissions demonstrate that the as-prepared sample is suitable for advanced information encryption and anti-counterfeiting.

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Persistent luminescence (PersL) phosphor is a glow‐in‐the‐dark material that has been widely applied. Here, we report a multicolor PersL phosphor Sr2Ga2GeO7:Pr3+. The PersL color can be tuned from deep red to blue. It reveals that the luminescent color modulation of the Sr2Ga2GeO7:Pr3+ phosphor is essentially associated with the cross‐relaxation effect of Pr3+ in the host with low‐phonon assistance energy. The PersL lifetime of the multicolor phosphors can be also tuned. Based on the unique features of Sr2Ga2GeO7:Pr3+ phosphor, some simple PersL images are fabricated to emit dynamic multicolor information, and it shows that the PersL image even depicts dynamic multicolor anticounterfeiting.