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Science 5 June 2009:
Vol. 324. no. 5932, pp. 1309 - 1312
DOI: 10.1126/science.1172104
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Reports

Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

Haimei Zheng,1,2,3 Rachel K. Smith,3,* Young-wook Jun,2,3,* Christian Kisielowski,1,2 Ulrich Dahmen,1,2,{dagger} A. Paul Alivisatos2,3,{dagger}

Understanding of colloidal nanocrystal growth mechanisms is essential for the syntheses of nanocrystals with desired physical properties. The classical model for the growth of monodisperse nanocrystals assumes a discrete nucleation stage followed by growth via monomer attachment, but has overlooked particle-particle interactions. Recent studies have suggested that interactions between particles play an important role. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution or by particle coalescence. Through the combination of these two processes, an initially broad size distribution can spontaneously narrow into a nearly monodisperse distribution. We suggest that colloidal nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies.

1 National Center for Electron Microcopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
2 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
3 Department of Chemistry, University of California, Berkeley, CA 94720, USA.

* These authors contributed equally to this paper.

{dagger} To whom correspondence should be addressed. E-mail: udahmen{at}lbl.gov (U.D.); alivis{at}berkeley.edu (A.P.A.)

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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Watching Nanocrystals Grow.
C. B. Murray (2009)
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