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Dipolar Structures in Colloidal Dispersions of PbSe and CdSe Quantum Dots

2007; American Chemical Society; Volume: 7; Issue: 9 Linguagem: Inglês

10.1021/nl0714684

1530-6992

Mark Klokkenburg, Arjan J. Houtepen, Rolf Koole, Julius W. J. de Folter, Ben H. Erné, Ernst van Faassen, Daniël Vanmaekelbergh,

Iron oxide chemistry and applications

We show by cryogenic transmission electron microscopy that PbSe and CdSe nanocrystals of various shapes in a liquid colloidal dispersion self-assemble into equilibrium structures that have a pronounced dipolar character, to an extent that depends on particle concentration and size. Analyzing the cluster-size distributions with a one-dimensional (1D) aggregation model yields a dipolar pair attraction of 8-10 kBT at room temperature. This accounts for the long-range alignment of the crystal planes of individual nanocrystals in self-assembled superstructures and for anisotropic nanostructures grown via oriented attachment.