Dipolar structures in colloidal dispersions of PbSe and CdSe quantum dots

Nano Lett. 2007 Sep;7(9):2931-6. doi: 10.1021/nl0714684. Epub 2007 Aug 22.


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.

MeSH terms

  • Cadmium Compounds / chemistry*
  • Colloids / chemistry*
  • Crystallization / methods*
  • Lead / chemistry*
  • Macromolecular Substances / chemistry
  • Materials Testing
  • Molecular Conformation
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Nanotechnology / methods*
  • Particle Size
  • Quantum Dots*
  • Selenium Compounds / chemistry*
  • Surface Properties


  • Cadmium Compounds
  • Colloids
  • Macromolecular Substances
  • Selenium Compounds
  • lead selenide
  • Lead
  • cadmium selenide