Pyrene-based aggregation-induced emission luminogens (AIEgens) with less colour migration for anti-counterfeiting applications

Traditional luminescent materials are subject to aggregation-caused quenching, which limits their use for high-technological applications in the solid state. In an attempt to address such issues when using luminescent materials in fluorescent inks, by taking advantage of the aggregation-induced emission (AIE) behaviour, this article presents a set of pyrene-based AIEgens which possess high thermal stability, excellent fluorescence properties, and good biocompatibility. These AIEgens can be utilized as fluorescent inks for anti-counterfeiting applications at ultralow/low concentration (0.004–0.5 wt%) (weightAIEgens : weightbinder = 5 : 125 000–5 : 1000) with slight colour migration (<27 nm) for different printing substrates. The use of such a fluorescent ink containing pyrene-based AIEgens has extended the scope of application over the range from ultralow to high concentration thereby avoiding the aggregation-caused quenching (ACQ) effect. Additionally, this system would lower the product cost, and be beneficial for the environment. The high-quality fluorescence pattern was found to exhibit good printability on different types of paper by old printing technology (screen printing technology). This work highlights that pyrene-based AIEgens are excellent candidates for use in anti-counterfeiting, and these results have the potential to enrich the practical applications of AIEgens in both academic and industrial fields.