Inkjet-printing-based structural coloring for anti-counterfeit applications

We show a novel anti-counterfeiting technique using mono-layered self-assembled photonic crystals (SAPCs), which are simply fabricated by inkjet material printers. These patterned photonic crystal layers not only provide stealth ability to avoid pattern detection from counterfeiters but also generate multiple colorful holograms under strong illumination on different viewing angles for complex cryptography. In addition, the number of SAPC arrays in a matrix format controls optical intensities, thus yielding an efficient anti-counterfeiting function. The mono-layered SAPCs show practical significance and remarkable potential in authentication of invaluable products. To date, this structural color-based anti-counterfeiting technique has not been demonstrated to the best of our knowledge.