MIT’s particles adorned with ‘rare-earth up-converting nanocrystals’ (via MIT)
People have been counterfeiting just about everything since the dawn of humankind. There is literally nothing that hasn’t been copied and sold on the consumer markets. Watches, shoes, wine, medication, software and of course money have all been replicated and sold to duped customers who thought they were getting the real deal. Companies have taken great strides in trying to incorporate anti-counterfeit devices into their products, however the knock-offs show no sign of slowing down even with those devices in place. To help curb counterfeiting, researchers from MIT have developed a tiny particle that can be read by smartphones to confirm their legitimacy.
The particles are invisible to the naked eye - containing multi-colored stripes of nanocrystals that shine brightly when exposed to near IR light. The particles are robust enough to withstand the rigors of extreme temperatures as well as heavy wear (incorporated into clothing), which makes them great for incorporation into luxury goods, electronics and even currency. The particles themselves are 200-microns in length, made from different polymers and incorporate several different colored ‘rare-earth up-converting nanocrystals’, which are doped with several IR reflective elements, including gadolinium, erbium, and thulium. The researchers were able to tune the crystals to emit any number of colors (at this point 9 in all) by altering the ratios of the elements, which was done by using stop-flow lithography (shapes imprinted on parallel streams of liquid monomers with long chains becoming polymers). Reading the particles does not require expensive decoder equipment like those found in most micro anti-counterfeit technologies. Instead, any smartphone outfitted with a 20X camera lens are able to image the tiny particles when exposed to near IR light, like those emitted by common laser pointers. The researchers are looking to refine the smartphone technique by developing a corresponding app that will reveal exactly what elements were used in the nanocrystals, thereby providing another barrier against counterfeiters.
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