Highly efficient transfer of water-soluble ZnS:Mn2+ nanocrystal into organic phase by 1-dodecanethiol

The 3-mercaptopropionic acid (MPA) capping water-soluble ZnS:Mn2+ nanocrystal was successfully transferred into organic phase by using 1-dodecanethiol in presence of sodium hydroxide as phase-transfer agent. The MPA ligand can be replaced completely by the long chain thiol even in a single water phase system. It is proposed that the conversion of 1-dodecanethiol into 1-dodecnethiolate can reduce the Gibbs energy of the reactions concerned in the ligand-exchange process, thus allowing complete ligand-exchange reaction and highly efficient transfer of the water-soluble nanocrystal into organic phase. In addition, the surface state related luminescence of the water-soluble ZnS:Mn2+ nanocrystal is suppressed greatly after being transferred into organic phase.