abstract |
The invention provides novel biocompatible upconversion nanoparticle (UCNP) that comprises a core of cubic nanocrystals (e.g., comprising α-Na Ln a , Ln b Ln c F 4 ) and an epitaxial shell (e.g., formed from CaF 2 ; wherein Ln b is Yb), and related methods of preparation and uses thereof. |