Developing color-tunable long afterglow anti-counterfeiting materials using cucurbit[6]uril and classical aggregation-caused quenching compounds through multiple non-covalent interactions

This investigation focuses on the utilization of cucurbit[6]uril (Q[6]) as the host compound for the development of long-lasting afterglow materials. By strategically manipulating the outer surface interactions of Q[6], classical aggregation-caused quenching (ACQ) compounds such as fluorescein sodium (FluNa) and calcein sodium (CalNa) were transformed into afterglow materials with varying colors and durations upon exposure to ultraviolet light. This transformation was facilitated through a host-guest doping method combined with coordination with metal ions. Even at a reduced doping concentration of 5 × 10^–5 wt%, the materials exhibit remarkable afterglow properties, lasting up to 2s, with a phosphorescence lifetime of up to 150 ms. Moreover, by adjusting the concentration of the guest compound, the persistent luminescence color of the materials could be easily transitioned from orange to yellow and subsequently to green. These findings suggest that the developed afterglow materials hold significant potential for multi-level anti-counterfeiting and information encryption applications when exposed to ultraviolet light. The supramolecular assembly strategy, which relies on the outer surface interactions of cucurbit[n]uril, offers a simpler and more efficient approach to crafting multi-color luminescent materials. Additionally, this method opens avenues for enhancing the application potential of aggregation-caused quenching (ACQ) compounds in various technological domains.