Researchers at Shiv Nadar University Develop an Invisible Security Ink


New Delhi: Shiv Nadar University, a leading multidisciplinary and research-oriented university, today announced that its research team comprising Dr. Debdas Ray, Associate Professor, and his doctoral student, Mr. Harsh Bhatia, from the Department of Chemistry, have created a unique ‘security ink’. The ink is not visible under normal lighting conditions, but the inked data can get revealed when placed under ultraviolet (UV) light sources. The research has used organic compounds, which are environment friendly, low in toxicity and not harmful to the human body, to develop this ink.

The ink by virtue of its chemical composition can alter its emission abilities under specific light conditions, thereby giving it the ability to provide additional layers of security to enhance its anti-counterfeit capabilities. Thus, it can provide a higher degree of safety and authenticity to a host of government documents (stamp-papers, passports, cheques, etc), currency, private classified documents as well as night-vision products used by private and government agencies.

Highlighting the importance of this invention, Dr Rupamanjari Ghosh, Vice-Chancellor, Shiv Nadar University, Uttar Pradesh, said, “At Shiv Nadar University, we are dedicated to create a research-based culture focused on providing creative and sustainable solutions to myriad problems faced by our country and the globe. An intriguing result observed in our Chemistry research laboratory has led to this useful, quality invention, and I would like to congratulate our research team for their work. Security ink market is expected to grow at roughly 8.3% over the next five years owing to rise in forgery and counterfeiting activities, to reach US$ 1.3billion in 2024, up from US$ 941.8 million in 2019. This indigenous research may give us an edge.”

The ink is made with the help of a commercially available polymer known as polyvinyl alcohol, dissolved in an organic solvent, either tetrahydrofuran or ethanol. After writing the characters with this ink, the paper is allowed to dry at ambient conditions for four hours, and afterwards it can be used for intended applications.

This security ink phenomenon incorporates the elements of both fluorescence (emission of light immediately after light exposure) and phosphorescence (in which the absorbed radiation is re-emitted on a slightly longer timescale). When the UV light is switched on, the characters become visible in a white background due to the involvement of both fluorescence and phosphorescence, and as soon as the light is switched off, the characters remain visible in a different colour only for a fraction of a second, due to phosphorescence.

The research has been published in the prestigious scientific journal, The Journal of Physical Chemistry.