Advanced Security Ink to Combat Counterfeiting

• 22 Mar 2025

Source: TH 

Scientists have developed a nanoparticle-based security ink to improve anti-counterfeiting measures in currency notes and sensitive documents.  

Nanoparticle-based Security Ink: 

• Composition: Made of Sr₂BiF₇ (strontium bismuth fluoride) nanoparticles doped with erbium and ytterbium ions, synthesized via a cost-effective coprecipitation technique. 
• Synthesis: Involves dissolving metal salts, adding a precipitating agent (e.g., NaOH or ammonia), followed by separation, purification, and drying for uniform nanoparticle mixing. 
• Unique Properties: Exhibits fluorescence under multiple wavelengths—blue (365 nm UV), magenta (395 nm UV), and orange-red (980 nm near-infrared)—ensuring high security against counterfeiting. 
• Advantages: Cost-effective, scalable, and environmentally stable. 
• Challenges & Future Scope: Currently tested for screen printing, with research underway for offset printing to enhance security in banknotes and passports. 

Currency Notes Printing: 

• Banknotes in India are printed at 4 currency presses: 2 under the Central Government’s Security Printing and Minting Corporation of India Ltd. (SPMCIL) at Nasik and Dewas and 2 under the RBI’s Bharatiya Reserve Bank Note Mudran Private Ltd. (BRBNMPL) at Mysuru and Salboni.

Read More: Ink to Curb Fake Printing of Passports and Counterfeiting of Currency Notes, Nanotechnology