The optical microscopy images of the same area on the diamond-PUF before and after a series of extreme treatments. Image: Chi et al, Nature Communications

High security anti-counterfeit labels

31 July 2023

A team of researchers from the University of Hong Kong have developed a new anti-counterfeiting technology using diamond microparticles. Dr Zhiqin Chu of the Department of Electrical and Electronic Engineering at the University of Hong Kong created unique and unreplicable anti-counterfeit labels known as PUFs (Physically Unclonable Functions) by scattering diamond microparticles onto silicon plates using a technique chemical vapour deposition.

The team's findings were published in the journal Nature Communications. The research was conducted in collaboration with researchers at Sun Yat-sen University in Guangzhou and Peking University in Beijing.

Each diamond microparticle varies in size and shape, creating distinct light scattering patterns that form a unique fingerprint for each label. This makes them virtually impossible to counterfeit. An additional layer of security comes from the diamond defects called silicon-vacancy (SiV) centers, which give the particles a distinctive near-infrared photoluminescence under green light.

The labels can withstand high temperatures, chemical exposure, and physical damage. And at a cost of only US$1 to produce 10,000 labels, they present a commercially viable solution.

Counterfeiting has become an increasing menace, causing massive economic losses and posing risks to health and safety across industries from pharmaceuticals to electronics. While anti-counterfeiting technologies like holograms and RFID tags are growing more advanced, counterfeiters have kept pace with increasingly sophisticated copying techniques.

Dr Chu believes these diamond-based PUFs provide the solution that counterfeiters cannot mimic. The labels' unique optical signatures can be digitized into highly secure codes readable by smartphone scanners or microscopes. Their resilience makes them suitable for commercial applications.

Dr Chu said the next phase is focused on real-world application of the technology. The labels are poised to provide companies with a powerful new tool in the ongoing fight against counterfeiting. Their uniqueness, resilience, affordability and smartphone compatibility give them an edge over existing anti-counterfeiting methods.

As counterfeiters continue to step up their game with more sophisticated fakery, this diamond-based tech could be the key to staying one step ahead. Dr Chu and his colleagues have opened up promising new possibilities for protecting brands, consumers and economies from the damaging impacts of counterfeit goods.