Hexanedioic acid mediated surface–ligand-exchange process for transferring …

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 …