Multicolor Fluorescent Inks Based on Lanthanide Hybrid Organogels for Anticounterfeiting and Logic Circuit Design

Abstract

With the rapid development of information technology, the encrypted storage of information is becoming increasingly important for human life. The luminescent materials with a color-changed response under physical or chemical stimuli are crucial for information coding and anticounterfeiting. However, traditional fluorescent materials usually face problems such as a lack of tunable fluorescence, insufficient surface-adaptive adhesion, and strict synthesis conditions, hindering their practical applications. Herein, a series of luminescent lanthanide hybrid organogels (Ln-MOGs) were rapidly synthesized using a simple method at room temperature through the coordination between lanthanide ions and 2,6-pyridinedicarboxylic acid and 5-aminoisophthalic acid. And the multicolor fluorescent inks were also prepared based on the Ln-MOG and hyaluronic acid, with the advantages of being easy to write, coloradjustable, and water-responsive discoloration, which has been applied to paper-based anticounterfeiting technology. Inspired by the responsiveness of the fluorescent inks to water, we designed a logic system that can realize single-input logic operations (NOT and PASS1) and double-input logic operations (NAND, AND, OR, NOR, XOR). The encryption of a binary code can be actualized utilizing different luminescent response modes based on the logic circuit system. By adjusting the energy sensitization and luminescence mechanism of lanthanide ions in the gel structure, the information reading and writing ability of the fluorescent inks were verified, which has great potential in the field of multicolor pattern anticounterfeiting and information encryption.

An acid-chromic luminescent lanthanide metallogel for time-dependent information encryption and anti-counterfeiting

“…Lanthanide metallogels, driven by dynamic coordination interactions, π–π stacking, hydrogen bonding, van der Waals forces, or other intermolecular non-covalent interactions, offer distinct advantages in the realms of information encryption and anti-counterfeiting. 7–9 These advantages stem not only from their unique optical properties—long luminescence lifetimes, good monochromaticity, and large Stokes shifts—but also from their stimulus-responsive characteristics. 10,11…”

“…For example, Niu et al reported lanthanide-based multicolor fluorescent gel inks that change color in response to water stimuli for anti-counterfeiting purposes. 9 Chen et al developed a thermal-responsive gel, enabling the decryption of loaded secret information only under combined heat and UV stimulation. 12 Zhao et al designed a gel with varied emission colors for quick response (QR) codes and ASCII encryption.…”