FLUORESCENT
SECURITY INK : SCIENCE & TECHNOLOGY
NEWS:
Indian team makes doubly secure ink to thwart counterfeiting
WHAT’S IN THE
NEWS?
Scientists
from the Institute of Nano Science and Technology (INST), Mohali, and the
Bhabha Atomic Research Centre (BARC), Mumbai, have developed a novel security
ink using strontium bismuth fluoride (Sr2BiF7) nanoparticles.This new
ink fluoresces under both UV and near-infrared (IR) light, offering enhanced
security against counterfeiting.
Security
Printing:
- Security printing involves using various techniques
to prevent counterfeiting of important documents such as banknotes,
passports, cheques, and branded consumer goods.
Security
Features in Printing:
- Optically Variable Ink: Ink
that changes color when viewed from different angles.
- Watermarks and Holograms:
These are used to provide additional authentication and protection against
forgeries.
- Security Threads: Embedded within currency notes to prevent
duplication and enhance security.
- Raised Textures and Shapes:
These allow tactile verification and are often used in currency and other
security materials.
- Digital Watermarks and Barcodes: Used
for electronic verification by scanning devices.
- RFID Chips in Passports:
Enable machine-readable authentication and provide more security.
Nanoparticle-Based
Fluorescent Ink:
- One major security feature in Indian banknotes is
the use of fluorescent ink in the number panel, which is visible
only under UV light.
- The new ink developed by INST and BARC scientists
offers an advanced level of security due to its dual fluorescence.
- Properties of Nanoparticles:
- Size Below 100 nm: This allows nanoparticles to interact
uniquely with light and magnetic fields.
- High Reactivity: Enhances the chemical stability and
durability of the ink.
- Improved Optical Properties:
Alters fluorescence behavior when exposed to different wavelengths of
light.
- The ink is formulated using strontium bismuth
fluoride (Sr2BiF7) nanoparticles doped with lanthanide ions
(erbium and ytterbium).
- The coprecipitation technique was employed
to synthesize these nanoparticles, where metal salts were dissolved in a
solvent and precipitated using a chemical agent under stirring
conditions.
- The synthesized nanoparticles were then blended
with polyvinyl chloride (PVC) ink and used in screen printing
for creating security markings.
- Under 395-nm UV light, the ink fluoresces magenta,
while under 980-nm near-IR light, it emits orange-red
light.
- This dual fluorescence provides a robust layer of
security, making it harder for counterfeiters to replicate.
- Comparison with Other Inks:
- INST-BARC Ink: Uses Sr2BiF7 doped with lanthanides,
exhibiting dual fluorescence.
- CSIR-NPL Ink: Uses gadolinium vanadate (GdVO4)
doped with europium, which emits red and green fluorescence.
- Researchers have noted that extremely high quantum
yield is not essential for security applications, as the ink provides
sufficient brightness under various lighting conditions.
About
Quantum Yield:
- Quantum yield quantifies the efficiency of a photophysical
or photochemical process. It is defined as the ratio of the number of
specific events (e.g., photon emission) to the number of photons absorbed
by the system.
- Applications of Quantum Yield:
- Fluorescence Spectroscopy:
Measures the efficiency of fluorescence processes, essential for
designing fluorescent probes in biological and analytical fields.
- Photochemical Reactions:
Determines how many molecules undergo a photochemical transformation per
absorbed photon.
- Photosynthesis Research:
Used to evaluate the efficiency of photosynthetic organisms in converting
light into chemical energy.
- Material Science and Nanotechnology:
Evaluates materials like quantum dots and nanoparticles,
especially in light-emitting applications such as displays and
photovoltaic cells.
About
Counterfeiting:
- Counterfeiting refers to the act of making imitation goods,
currency, documents, or trademarks without authorization, aiming to
deceive consumers or gain illicit benefits.
- Types of Counterfeiting:
- Currency Counterfeiting:
Creating fake money, including banknotes, coins, or digital currencies.
- Product Counterfeiting:
Manufacturing fake versions of branded goods such as luxury items,
electronics, pharmaceuticals, and consumer products.
- Document Counterfeiting:
Forging documents such as passports, identity cards, educational
certificates, and legal papers.
- Intellectual Property (IP) Counterfeiting:
Copying patented designs, trademarks, or copyrighted content without
permission.
The
development of the dual fluorescence ink enhances security features in
printing, making it more challenging for counterfeiters to replicate important
documents like currency and passports.
Source: https://www.thehindu.com/sci-tech/science/indian-team-makes-doubly-secure-ink-to-thwart-counterfeiting/article69281571.ece