Hexanedioic acid mediated surface-ligand-exchange process for transferring NaYF4:Yb/Er (or Yb/Tm) up-converting
Qingbin Zhang1, Kai Song, Junwei Zhao
1Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, PR China.
Abstract:
Water-soluble and carboxyl-functionalized up-converting rare-earth nanoparticles (UCNPs) are obtained via an efficient surface-ligand-exchange procedure. Hexanedioic acid molecules are employed to replace the original hydrophobic ligands in diethylene glycol solvent at high temperature. Various characterizations indicate the ligand-exchange process has negligible adverse effect on the quality of the UCNPs. The resulting hydrophilic UCNPs show small size, strong up-converting emission and high water stability. The specific molecular recognition capacity of avidin-modified hydrophilic UCNPs confirms that hydrophilic UCNPs are suitable for potential biological labeling.
