title: Ultra-large-scale syntheses of monodisperse nanocrystals.
abstract: The development of nanocrystals has been intensively pursued, not only for their fundamental scientific interest, but also for many technological applications. The synthesis of monodisperse nanocrystals (size variation <5%) is of key importance, because the properties of these nanocrystals depend strongly on their dimensions. For example, the colour sharpness of semiconductor nanocrystal-based optical devices is strongly dependent on the uniformity of the nanocrystals, and monodisperse magnetic nanocrystals are critical for the next-generation multi-terabit magnetic storage media. For these monodisperse nanocrystals to be used, an economical mass-production method needs to be developed. Unfortunately, however, in most syntheses reported so far, only sub-gram quantities of monodisperse nanocrystals were produced. Uniform-sized nanocrystals of CdSe (refs 10,11) and Au (refs 12,13) have been produced using colloidal chemical synthetic procedures. In addition, monodisperse magnetic nanocrystals such as Fe (refs 14,15), Co (refs 16-18), gamma-Fe(2)O(3) (refs 19,20), and Fe(3)O(4) (refs 21,22) have been synthesized by using various synthetic methods. Here, we report on the ultra-large-scale synthesis of monodisperse nanocrystals using inexpensive and non-toxic metal salts as reactants. We were able to synthesize as much as 40 g of monodisperse nanocrystals in a single reaction, without a size-sorting process. Moreover, the particle size could be controlled simply by varying the experimental conditions. The current synthetic procedure is very general and nanocrystals of many transition metal oxides were successfully synthesized using a very similar procedure.
authors.affiliation: National Creative Research Center for Oxide Nanocrystalline Materials and School of Chemical Engineering, Seoul National University, Seoul 151-744, Korea.
authors.forename: Jongnam
authors.initials: J
authors.lastname: Park
authors.forename: Kwangjin
authors.initials: K
authors.lastname: An
authors.forename: Yosun
authors.initials: Y
authors.lastname: Hwang
authors.forename: Je-Geun
authors.initials: JG
authors.lastname: Park
authors.forename: Han-Jin
authors.initials: HJ
authors.lastname: Noh
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Park
authors.forename: Nong-Moon
authors.initials: NM
authors.lastname: Hwang
authors.forename: Taeghwan
authors.initials: T
authors.lastname: Hyeon
mesh_terms: D003460:Crystallization / Q000379:methods*; D019544:Equipment Failure Analysis; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D006358:Hot Temperature; D008420:Manufactured Materials; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties
chemical_list: D005290:Ferric Compounds; D012997:Solvents; C000499:ferric oxide