Lead-Free Manganese Halide Perovskite for Minute-Level Dynamic Time-Gating Anticounterfeiting

The dynamic time-gating anticounterfeiting based on phosphorescence materials is the current hot topic of research. However, the short change time from nanosecond-level fluorescence false information to μs-level fluorescence correct information makes it easily deciphered just by turning off ultraviolet (UV) light. Herein, we first reported a new type of minute-level dynamic time-gating anticounterfeiting technology based on the ethanol-induced phase transition between the red-emitting CsMnBr₃ crystals and green-emitting Cs₃MnBr₅ crystals. Our results show that the dissolution of MnBr₂·2H₂O from CsMnBr₃ into ethanol triggers the phase transition. Moreover, the time of phase transition can be adjusted by mixing with different (3-aminopropyl)triethoxysilane (APTES) concentrations. By using CsMnBr₃ and APTES-CsMnBr₃ with different phase-transition times, the true information on "SEO" can be designed to show only in the conditions of specific stimulus (ethanol) and specific time range. Otherwise, the false information on "SEU" or "888" is shown. In comparison to previously reported dynamic time-gating anticounterfeiting technology based on phosphorescence materials, the current reported minute-level dynamic time-gating anticounterfeiting technology based on phase transition increased the difficulty of decryption. Moreover, the combination of nontoxic fluorescence materials and daily life available stimulus (ethanol) makes the current anticounterfeiting technology have great practical value.