Upconverting Films

This Small Business Innovation Research (SBIR) Phase I project will develop highly bright and stable doped nanocrystal/polymer nanocomposite thin film as light up-converting medium for infrared light visualization applications. Upconversion of higher energy light from lower energy radiation are realized through the use of trivalent lanthanide ions, actinide ions, or transition metals doped in a solid-state host. Oxides and halides are the two commonly used hosting materials for upconversion ions. In halides, the nonradiative rate is low and the upconversion luminescence efficiency is high. However, many halides are sensitive to moisture and unstable in air. Oxides are stable in air, but the upconversion of oxides is usually very low due to the rapid relaxation induced by large phonon energy. In this SBIR project, several doped semiconductor nanocrystals with the high upconversion efficiency and stability will be developed as the upconversion medium. These nanocrystals will be dispersed into optically transparent polymer matrices through an in situ polymerization process to form an upconversion thin film that can be used in infrared visualization instruments.