Monodisperse silica-coated polyvinyl-pyrrolidone/NaYF4 nanocrystals with multicolor upconversion fluorescence emission

Abstract

(Figure Presented) In full color: Ultrafine lanthanide-doped polyvinylpyrrolidone/NaYF4 nanocrystals with narrow size distribution were synthesized and found to disperse well in water and many organic solvents. Silica was coated onto the nanocrystals to form a uniform thin layer. Highly efficient upconversion fluorescence was observed from both uncoated and silica-coated PVP/NaYF4 nanocrystals doped with Yb/ Er or Yb/Tm (see picture). © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.