New Delhi

A team of scientists at the Institute of Nano Science and Technology (INST), part of the Department of Science and Technology, has developed a new type of security ink aimed at combating counterfeiting in currency, certificates, branded goods, and medicines. This innovative ink incorporates rare earth ions known for their unique luminescent properties, particularly those of bismuth.

By leveraging these rare earth materials, the researchers created a groundbreaking security ink that features luminescent nanomaterials. This ink exhibits excitation-dependent luminescence, which means it emits visible light under ultraviolet and near-infrared light, surpassing the capabilities of current covert security tags that are only visible under UV light and can be easily copied.

The new ink displays different colors when exposed to various light wavelengths: it shines vibrant blue under 365 nm light, pink under 395 nm light, and orange-red under 980 nm near-infrared light. Additionally, it maintains its effectiveness across different light, temperature, and humidity conditions.

The scientists used a straightforward co-precipitation method at 120 degrees Celsius to create the luminescent nanomaterial, which was then mixed with commercially available PVC ink and applied using screen printing. This advancement not only aids in the fight against counterfeiting but also allows consumers and manufacturers to easily verify the authenticity of their products.