Reporting in Nanotechnology, nanoscale fingerprint patterns are generated by simply casting fluorescent dye-coated silver nanowires onto a transferrable flexible polyethylene terephthalate (PET) film. The direction and target markers ("KAIST" and "X") are patterned by a photolithographic technique to provide positional information for identification and the nanowires are cast onto it. Then, using an optical microscope, the resulting unique fingerprint patterns can be visually authenticated in a simple and straightforward manner, as shown fully in the figure above.

Widely achievable

Advantages of this technique are the simple preparation of fingerprint patterns and the authenticity verification. The technique is simple enough that anyone can prepare these barcodes. Fingerprint patterns can be visually authenticated in a simple and straightforward manner by using an optical microscope, which allows customers to immediately determine whether products are authentic. Although generating a fingerprint pattern is quite simple, counterfeiting the pattern is essentially impossible because it is based on natural randomness. Counterfeiting such a fingerprint pattern is impractical and expensive; the cost of replicating it would be higher than the value of the typical target item being protected.

Further levels of security

While the likelihood of obtaining identical patterns of randomly orientated nanowires is practically zero, the fluorescent dyes add another layer of complexity, as does increasing the density of nanowires. Expanding this concept further, many products such as paper documents will have a profile of defects on the nanoscale. As long as this profile can be recorded, it will provide a unique barcode as a result of naturally occurring randomness. The researchers hope that their concept of nanoscale fingerprints can be widely applicable in various anti-counterfeit activities.

More information about the research can be found at Nanotechnology 25 155303.