“No way works”… UNIST develops non-counterfeit bill technology

Input 2021.01.05 01:00

Prof. Jinseok Lee’s team develops nanoparticles that simultaneously realize structure color and hologram
Nature Materials announced… “Commercialized as a sticker for product activation within the year”

Researchers in Korea have developed a technology for banknotes that cannot be counterfeited by conventional methods. The research team plans to commercialize it as a genuine product authentication sticker for cosmetics and other products by the end of this year, and then apply it as a coating material for anti-counterfeiting design of bills.

The Ulsan Institute of Science and Technology (UNIST) announced on the 5th that the research team of Professor Ji-Seok Lee of the Department of Energy and Chemical Engineering has developed’conjugated polymer particles’ that can implement several’anti-counterfeiting devices’ at once. The research results were also published in the international academic journal’Nature Materials’.

Usually, counterfeit devices are coated on the surface of the bill to prevent counterfeiting. Typical examples are’structure color’, which changes color depending on the viewing direction, and’hologram’, which changes shape. Structural colors and holograms are designed to be difficult to imitate, but as time goes by, imitation techniques are gradually becoming more sophisticated. In 2019, counterfeit bills that were elaborately produced and pasted on a band-shaped hologram with a high-performance printer were also found on the market.

The research team developed a material that can implement both at once so that existing techniques that imitate either structure color or hologram cannot be used. It was named’Conjugated Polymer Particles’ and has a size of 200 to 300 ㎚ (nanometer·1 billionth of a meter) as it is designed with a special structure. Characters or images made of the particles change color (structure color) and shape (hologram) every moment depending on the direction in which the light enters.

The research team also developed a process that enables mass production of these particles. After attaching several particles in a grid shape, he succeeded in drawing a masterpiece by arbitrarily adjusting the structure color for each particle.

Professor Lee Jin-seok said, “First of all, we plan to make a sticker for authenticating cosmetics and commercialize it by the end of the year,” he said. “After that, we will apply it as an edible sticker that can be pasted on pill capsules and as a coating material for anti-counterfeiting devices.”