A facile synthesis of multicolor polystyrene microspheres encapsulating upconversion fluorescent nanoparticles

Abstract

Monodisperse polystyrene (PS) microspheres encapsulating rare-earth ion doped β-NaYF4 upconversion fluorescent nanocrystals, with ca. 400 nm in diameter, have been synthesized successfully using a microemulsion polymerization method. Single PS microsphere contains more than 20 β-NaYF4 nanocrystals. The microspheres emit strong NIR-to visible upconversion fluorescence upon excitation by a 980nm laser. Use of this method could be extended to synthesis of PS microspheres encapsulating other functional nanocrystals. © 2008 Springer-Verlag.