In this evolving world, counterfeiting is also evolving in advanced ways and counterfeiters are turning out to be more proficient to counterfeit security features effectively by utilising all advanced technologies and tools to perform their unethical activities.

Over the decades, a huge amount has been invested in developing several anti-counterfeiting technologies to limit the opportunities for passport fraud, but authorities are still struggling to stay one step ahead of the counterfeiters. So far, numerous multimodal luminescent materials have been explored using various combinations for the fabrication of security inks. But the biggest concern with these anti-counterfeiting technologies is that they all entirely rely on luminescence only. Although the pairing of materials is rare, they still get easily decoded using advanced technological instruments and tools by deciphering their chemical composition, structures, and ratio.

To overcome these obstacles a new class of multi-functional security pigments has been introduced with two properties combined — optical and magnetic — to obtain more efficient security inks for important documents such as banknotes and bank cheques which can be easy to detect and trace but hard to replicate.

CSIR-National Physical Laboratory (CSIR-NPL), New Delhi, has proposed a cost-effective golden ink that is one step ahead to provide more security to important documents. It is a new strategy to design a novel and inexpensive Multi-functional Luminescent Pigment (MLSP) based Golden Ink and has demonstrated its potential applications to save the authenticity of passports with a golden appearance in visible light.

The MLSP is successfully synthesised using three ingredients of Gd0.8Eu0.2VO4 rods, Zn0.98Cu0.02S particles, and Gd0.87Tm0.03Yb0.1VO4 rods luminescent materials, which are responsible for red, green and blue emission with excitation wavelengths of 254 nm, 365 nm and 980 nm, respectively. Additionally, another important feature is also incorporated to enhance the security feature in terms of magnetic character recognitions using magnetic nanoparticles in the same MLSP to encrypt the personal and secret information of passport.

The proposed MLSI security ink with a golden appearance having entangled RGB luminescent and magnetic features in single pigment formulated ink could be considered as a next-generation higher-level security feature to stop the counterfeiting problem of passport as well as bank cheques, government documents, pharmaceuticals, military equipment and many more.

This work was published in the journal Small.

Reference
Kanika, Kedawat, G, Srivastava, S, & Gupta, BK (2023). A strategic approach to design multi?functional RGB luminescent security pigment based golden ink with myriad security features to curb counterfeiting of Passport. Small, 2206397. https://doi.org/10.1002/smll.202206397