Aggregation induced luminescence chromism molecule for preparation of physically unclonable function labels

Organic stimuli-responsive luminescent materials have attracted much attention due to their great potential in security fields such as fluorescent inks and information security. However, the widespread aggregation quenching effect limits the organics’ practical application in anti-counterfeiting technology. To overcome this challenge, this study developed a novel molecule 4-(4-phenyl-6-(pyren-1-yl)-1,3,5-triazin-2-yl)benzyl acrylate (PPTBA) which exhibits high luminescence efficiency in both monodisperse and aggregated states, with an obvious aggregation-induced emission color change. The copolymer P(NIPAM-PPTBA) was obtained by copolymerizing PPTBA and NIPAM (N-Isopropyl acrylamide). The polymer exhibits a blue-to-yellow luminescence chromism upon adding an appropriate amount of water. The polymer film can perfectly hide letters when combined with stamp technology and can be developed with water for general-purpose anti-counterfeiting verification. The polymer is utilized to prepare fluorescence physically unclonable functions (PUF) labels with a high-security level by using a convenient spraying technique. The random localization of polymeric domains yields unclonable surfaces with moderate uniformity, uniqueness, and good coding capacity. In particular, this PUF exhibits good temperature stability and photostability, and the luminescent hydrochromism of the polymer further enhances the encryption level. This work demonstrates the practicality and reliability of an organic light-emitting system for anti-counterfeiting applications and provides a realistic solution for preparing low-cost PUF.