Multimodal Dynamic and Unclonable Anticounterfeiting Using Robust Diamond Microparticles on Heterogeneous Substrate

Principal Investigator: Professor Zhiqin Chu (Assistant Professor, Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences)

This project is showcased as the Research Highlight (May – June 2024) in the third exhibition – Technology for Future in Innovation Wing Two

Project information


Counterfeiting is a global menace endangering financial security, national safety, and public health. Traditional methods like watermarks and QR codes are vulnerable due to deterministic fabrication. Unbreakable security labels with physical unclonable functions (PUFs) offer a promising solution. PUFs leverage inherent randomness to create unique identifiers like fingerprints. Here, diamond-based PUFs, utilizing the stochastic nature of artificial diamond microparticles with silicon-vacancy (SiV) centers, offer a robust and unforgeable solution, providing a new frontier in anti-counterfeiting technology that is both durable and secure.
Photo and electron microscopy images of the developed diamond PUF label
Representative multimode encoding process of the diamond-PUF labels

Achievement of the Project

  • T. Zhang, Q. Wang,* L. Shao,* Z. Chu* et al. Nat. Commun., 14, 2507 (2023).
  • PCT International Application No. PCT/CN2023/095744.
  • WO/CN Patent Application Publication No.: WO2024012060A1; CN117431061A.
  • Gold Medal and Great Special Award at The 8th International Invention Innovation Competition in Canada (iCAN 2023)

About the Scholar

Professor Zhiqin Chu received his PhD degree in Physics from The Chinese University of Hong Kong in July 2012. Professor Chu carried out his postdoctoral training (2014/04-2016/09) at The University of Stuttgart (Germany), and then worked as a Research Assistant Professor (2016/10-2018/10) in Department of Physics at The Chinese University of Hong Kong. Since November 2018, Professor Chu has been an Assistant Professor in Department of Electrical and Electronic Engineering (Joint Appointment with School of Biomedical Sciences), and established the Precision Biosensing & Biophysics (PBB) Laboratory at The University of Hong Kong. Professor Zhiqin Chu’s research interests include Precision Biosensing/Imaging; Diamond defects; Biophysics; Nanophotonics; and Materials-Biology Interface.

Press release

HKU Engineering team uses diamond microparticles to create high security anti-counterfeit labels

The press release article can be founded in HKU Press release (

Counterfeiting is a serious problem affecting a wide range of industries – from medicine to electronics, inflicting enormous economic losses, posing safety concerns and putting health at risk.

Counterfeiters and anti-counterfeiters are now locked in a technological arms race. Despite anti-counterfeiting tools becoming more and more high-tech – including holograms, thermochromic ink and radio frequency identification tags, fake products are becoming harder and harder to tell apart from the genuine articles because counterfeiters are using increasingly advanced technology.

Recently, a team of researchers led by Dr Zhiqin Chu of the Department of Electrical and Electronic Engineering of the University of Hong Kong (HKU), together with Professor Lei Shao of the School of Electronics and Information Technology of Sun Yat-sen University, and Professor Qi Wang from Dongguan Institute of Opto-Electronics of Peking University developed a pioneering technological solution that counterfeiters have no response to.

Dr Chu’s team created diamond-based anti-counterfeiting labels that are unique and known in the industry as PUFs – Physically Unclonable Functions.

The team made these labels by planting tiny artificial diamonds – known as diamond microparticles, on a silicon plate using a method called Chemical Vapour Deposition (CVD).

The diamond microparticles, all different in shape and size, form a unique pattern when they scatter on the silicon substrate. Such pattern is impossible to replicate and therefore scatters light in a unique way. Put simply, it forms a unique “fingerprint” than can be scanned using a phone.

The second level of uniqueness, and hence security, comes from the fact that these diamond microparticles have defects known as silicon-vacancy (SiV) centers.

SiVs give diamond microparticles a unique optical property – they emit near-infrared photoluminescence when a green light is shone on them, which makes them easily identifiable. These unique optic signatures can then be combined and digitized into codes of very high sophistication and security that can be read by a simple smartphone scanner and/or a confocal fluorescence microscope.

Very importantly, these diamond-based labels are highly suitable for the use in commercial products as they are extremely tough – in the trials they withstood heat, the action of chemicals and physical damage.

And, they are cheap – it costs just one US dollar to make 10,000 such labels of 200 µm × 200 µm dimensions. Moreover, because they are made from diamonds, these anti-copying labels would enhance the value of the product.  

The labels are ready to be used commercially, said Dr Chu, adding that the team’s next step is “to focus on the practical application”.

“Diamond anti-counterfeiting will be favoured in various high-end products such as jewellery, luxury goods, electronic products, and automobiles,” he said. 

The results of Dr Chu team’s work were published in Nature Communications in an article entitled “Multimodal dynamic and unclonable anticounterfeiting using robust diamond microparticles on heterogeneous substrate”.

Link to the paper:

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