Tuesday, September 11, 2012

Security printing of covert quick response codes using upconverting nanoparticle inks

Jeevan M Meruga, William M Cross, P Stanley May, QuocAnh Luu, Grant A Crawford and Jon J Kellar



Counterfeiting costs governments and private industries billions of dollars annually due to loss of value in currency and other printed items. This research involves using lanthanide doped β-NaYF 4 nanoparticles for security printing applications. Inks comprised of Yb 3+ /Er 3+ and Yb 3+ /Tm 3+ doped β-NaYF 4 nanoparticles with oleic acid as the capping agent in toluene and methyl benzoate with poly(methyl methacrylate) (PMMA) as the binding agent were used to print quick response (QR) codes. The QR codes were made using an AutoCAD file and printed with Optomec direct-write aerosol jetting ® . The printed QR codes are invisible under ambient lighting conditions, but are readable using a near-IR laser, and were successfully scanned using a smart phone. This research demonstrates that QR codes, which have been used primarily for information sharing applications, can also be used for security purposes. Higher levels ...



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