Smartphone-Identifiable Photoluminescent Nanoparticle-Based Multilevel Secured Tags by Electrical Microcontact Printing

To fight the boom in counterfeiting and especially the fraud of official documents, we propose herein original multilevel integrated security features: photoluminescent nanoparticle-based tags (PL tags). Using the electrical microcontact printing technique, PL tags are fabricated at large scale and are successfully integrated in the production line of plastic cards. We introduce COC-based stamps in the fabrication process to meet industrial constraints in terms of speed, cost and robustness. Depending on the resolution of security features, from several millimeters down to several micrometers, PL tags can also combine several degrees of reading and so security. Indeed, using a simple blue LED, they could be quickly identifiable by naked eye or a simple smartphone camera. In addition, they could also embed smaller features only readable with an optical microscope.