Multimode dynamic photoluminescent anticounterfeiting and encryption based on a dynamic photoluminescent material

Time-dependent dynamic multicolor afterglow of simple LiGa5O8:Eu3+/Tb3+particles for advanced anticounterfeiting and encryption

“…The LGO samples have a direct band gap of 4.9 eV according to the theory of Mott and Davis. 1,34 After Eu 3+ ion doping in LGO samples, the band gap appears to increase in Fig. 4b and Fig.…”

“…It shows that the deep traps are quickly charged and the energy transfers from deep traps to Eu 3+ ions by electron tunneling. 1,27 The red PL band at 616 nm occupies the main part of the spectrum at the beginning of irradiation. With the extension of the irradiation time, the deep traps are gradually filled.…”

A multicolor‐emitted phosphor for temperature sensing and multimode dynamic anti‐counterfeiting

“…As shown in Figure 3D, when the temperature rises from 298 to 473 K (with intervals of 25 K), the integrated PL intensity can be maintained at 119%, 114%, 113%, 114%, 113%, 116%, and 118% of the original. This PL‐integrated intensity enhancement phenomenon, also known as anti‐thermal quenching performance, is attributed to a thermally assisted ET process 34 . Photogenerated carriers can be captured via traps embedded in the materials.…”

“…This PL-integrated intensity enhancement phenomenon, also known as anti-thermal quenching performance, is attributed to a thermally assisted ET process. 34 Photogenerated carriers can be captured via traps embedded in the materials. Carriers in traps are regularly released for thermal disturbance, which contributes to increased luminescence intensity.…”

A dynamic irradiation-responsive material for advanced anti-counterfeiting in dark and bright fields

“…[4][5][6] Among the current anti-counterfeiting technologies, luminescence is widely regarded as one of the most ideal anti-counterfeiting technologies due to its good visibility, easy design, and the popularity of portable lamps as irradiation sources. [7][8][9] Generally, the basic feature of luminescence anticounterfeiting is that the anti-counterfeiting label is invisible in sunlight and only appears in the form of luminescence under irradiation of ultraviolet light. [10][11][12][13] However, after decades of practical applications, the feature of luminescence anticounterfeiting is well known and its security level has also dropped significantly and even some criminals can easily counterfeit the present luminescent labels by using substitutes.…”