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.