| abstract |
Provided are core-shell nanoparticles and methods of making and using the nanoparticles. The nanoparticles comprise a core comprising hexagonal phase p-NaYbF4 doped with Tm and shell comprising NaYF4, NaLuF4, or NaGdF4. The core-shell nanoparticles can be used to upconvert near infrared light to UV or visible blue light, which can polymerize photopolymerizable materials. The core-shell nanoparticles can be used in applications such as, for example, photolithography applications, photopatterning applications, fabrication of polymer coatings, medical applications, dental applications, and anti-counterfeiting applications. |