One of the endearing and enduring features of the structure of matter is sinilarity at different length scales, most powerfully articulated by Cyril Stanley Smith in terms of Hierarchy of Structures. While we had exmples of atoms and even polymeric chains forming quasicrystals, the recent report of nanocrystals self assembling as quasicrystals is fascinating and indicates that patterns of organization are indifferent to the identity of organizing entities.
Nature 461, 964-967 (15 October 2009) | doi:10.1038/nature08439; Received 6 April 2009; Accepted 13 August 2009
Quasicrystalline order in self-assembled binary nanoparticle superlattices
Dmitri V. Talapin1,2,5, Elena V. Shevchenko2,5, Maryna I. Bodnarchuk1, Xingchen Ye3, Jun Chen4 & Christopher B. Murray3,4
Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA
Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA
Department of Chemistry,
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
These authors contributed equally to this work.
Correspondence to: Dmitri V. Talapin1,2,5Elena V. Shevchenko2,5 Correspondence and requests for materials should be addressed to D.V.T. (Email: dvtalapin@uchicago.edu) or E.V.S. (Email: eshevchenko@anl.gov).
AbstractThe discovery of quasicrystals in 1984 changed our view of ordered solids as periodic structures1, 2 and introduced new long-range-ordered phases lacking any translational symmetry3, 4, 5. Quasicrystals permit symmetry operations forbidden in classical crystallography, for example five-, eight-, ten- and 12-fold rotations, yet have sharp diffraction peaks. Intermetallic compounds have been observed to form both metastable and energetically stabilized quasicrystals1, 3, 5; quasicrystalline order has also been reported for the tantalum telluride phase with an approximate Ta1.6Te composition6. Later, quasicrystals were discovered in soft matter, namely supramolecular structures of organic dendrimers7 and tri-block copolymers8, and micrometre-sized colloidal spheres have been arranged into quasicrystalline arrays by using intense laser beams that create quasi-periodic optical standing-wave patterns9. Here we show that colloidal inorganic nanoparticles can self-assemble into binary aperiodic superlattices. We observe formation of assemblies with dodecagonal quasicrystalline order in different binary nanoparticle systems: 13.4-nm Fe2O3 and 5-nm Au nanocrystals, 12.6-nm Fe3O4 and 4.7-nm Au nanocrystals, and 9-nm PbS and 3-nm Pd nanocrystals. Such compositional flexibility indicates that the formation of quasicrystalline nanoparticle assemblies does not require a unique combination of interparticle interactions, but is a general sphere-packing phenomenon governed by the entropy and simple interparticle potentials. We also find that dodecagonal quasicrystalline superlattices can form low-defect interfaces with ordinary crystalline binary superlattices, using fragments of (33.42) Archimedean tiling as the 'wetting layer' between the periodic and aperiodic phases.
Tags:
Share
You need to be a member of Materialia Indica to add comments!
Join this Ning Network