Halide modulated room-temperature phosphorescence from one-dimensional metal‒organic halides for time-resolved anti-counterfeiting

Room-temperature phosphorescence (RTP) materials have shown widespread applications in optoelectronic devices, biological imaging, molecular switches, safety systems, etc. Here, we report the design and synthesis of a series of metal‒organic halide materials with regulated phosphorescence and fluorescence dual emission properties. Their dual emission ratio and RTP lifetime can be facilely tuned by the halide substituent synthesis. Bright afterglow with various emission duration for the investigated materials can be identified by the naked eyes. DFT calculations reveal that the excited states exhibit halide‒ligand charge transfer (XLCT) character and the halide atoms play crucial role in their luminescence properties. Based on their regulatable dual emission and afterglow properties, a time-resolved anti-counterfeiting application is developed and avoids the over-dependence on equipment, which further provides feasible design strategy of advanced portable anti-counterfeiting technology.