Application in Anticounterfeiting for Multistimuli Smart Luminescent Materials Based on MOF-on-MOF

The generation of smart responsive materials that can perform multiple drastic optical outputs upon different triggers provides a good platform to encode and hide the information and create multilevel security. In this paper, a smart multiresponsive MOF-on-MOF material was reported using one MOF (HPU-14) as a platform to grow ZIF-8 on the outer layer, combining different emitter centers such as anthracene (ANT) and lanthanide ions (Ln(3+)) confined into two MOFs. Due to the existence of ANT in the pores of ZIF-8, this composite material can exhibit reversible photoswitching behavior under a 365 nm ultraviolet (UV) lamp and enable resetting and reusing dynamic anticounterfeiting application. Meanwhile, when treated by an acid/alkali gas, this material can also display reversible switching behavior under 254 nm UV irradiation, which is attributed to the loading of Ln(3+) on HPU-14. We demonstrated that this excellent practical anticounterfeiting material can decipher the right information only by following a strict stimuli sequence. Therefore, this MOF-on-MOF material synthesis technology for sophisticated counterfeiters, which makes the protected information highly secure, could open a new way to design multilevel anticounterfeiting materials.

Automated summary

This paper reports a smart multiresponsive MOF-on-MOF material that can exhibit multiple optical outputs under different triggers, showing reversible photoswitching behavior suitable for dynamic anticounterfeiting applications. The material can decode the correct information based on a strict sequence of stimuli, providing good effectiveness in preventing sophisticated counterfeiters from forging.