High Efficiency Up/Down Converting Nanoparticles

ABSTRACT: To address the need for covert, transparent optical taggants, which can upconvert and downconvert greater than 100 nm when stimulated by either 830 nm or 1064 nm laser light, a series of wide bandgap doped metal oxide nanoparticles will be developed and demonstrated. In Phase I, lanthanide-doped core-shell nanocrystals will be fabricated that are sufficiently small (e.g.<5 nm) that they do not cause Rayleigh or Mei scattering and can remain undetected on or when applied to surfaces. The doping type and concentration will be optimized for either down-conversion or up-conversion. Antenna-emitter architecture will be shown to have optimal conversion efficiency. A ligand coating will be developed which allows the nanoparticles to be dispersed in high density without agglomeration, be dispersed without clogging, and adhere to a variety of surfaces. If the schedule permits, we will conduct military sponsored field tests to demonstrate the performance of the taggants. In Phase II, the taggant efficiency will be optimized and the methods of manufacturing kg/day quantities will be developed. BENEFIT: The ability to tag individuals and materials is a powerful new tool for locating modern threats. Capabilities of a taggant include: tagging, tracking, and locating (TTL), combat identification (CID), identification of friend or foe (IFF), material control and tracking, access control, and others. The benefits of TTL are well recognized. The Defense Science Board"s 2004 study entitled"Transition to and from Hostilities"recommends a"Manhattan Project"approach to tagging, tracking, and locating. Commercial applications include anti-counterfeiting of money, tax stamps, high value documents, and high value goods.The ability to tag individuals and materials is a powerful new tool for locating modern threats. Capabilities of a taggant include: tagging, tracking, and locating (TTL), combat identification (CID), identification of friend or foe (IFF), material control and tracking, access control, and others. The benefits of TTL are well recognized. The Defense Science Board"s 2004 study entitled"Transition to and from Hostilities"recommends a"Manhattan Project"approach to tagging, tracking, and locating. Commercial applications include anti-counterfeiting of money, tax stamps, high value documents, and high value goods.