title: Synthesis of ligand-stabilized metal oxide nanocrystals and epitaxial core/shell nanocrystals via a lower-temperature esterification process.
abstract: The properties of metal oxide nanocrystals can be tuned by incorporating mixtures of matrix metal elements, adding metal ion dopants, or constructing core/shell structures. However, high-temperature conditions required to synthesize these nanocrystals make it difficult to achieve the desired compositions, doping levels, and structural control. We present a lower temperature synthesis of ligand-stabilized metal oxide nanocrystals that produces crystalline, monodisperse nanocrystals at temperatures well below the thermal decomposition point of the precursors. Slow injection (0.2 mL/min) of an oleic acid solution of the metal oleate complex into an oleyl alcohol solvent at 230 °C results in a rapid esterification reaction and the production of metal oxide nanocrystals. The approach produces high yields of crystalline, monodisperse metal oxide nanoparticles containing manganese, iron, cobalt, zinc, and indium within 20 min. Synthesis of tin-doped indium oxide (ITO) can be accomplished with good control of the tin doping levels. Finally, the method makes it possible to perform epitaxial growth of shells onto nanocrystal cores to produce core/shell nanocrystals.
authors.affiliation: Nanoscience Open Research Initiative, Materials Science Institute and Department of Chemistry and ‡Department of Chemistry, University of Oregon , Eugene, Oregon 97403, United States .
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ito
authors.forename: Shun
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Tatiana
authors.initials: T
authors.lastname: Zaikova
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Masuko
authors.forename: James E
authors.initials: JE
authors.lastname: Hutchison