Quasicrystalline order in self-assembled binary nanoparticle superlattices.
The discovery of quasicrystals in 1984 changed our view of ordered solids as periodic structures and introduced new long-range-ordered phases lacking any translational symmetry. 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 quasicrystals; quasicrystalline order has also been reported for the tantalum telluride phase with an approximate Ta{sub 1.6}Te composition. Later, quasicrystals were discovered in soft matter, namely supramolecular structures of organic dendrimers and tri-block copolymers, and micrometre-sized colloidal spheres have been arranged into quasicrystalline arrays by using intense laser beams that create quasi-periodic optical standing-wave patterns. 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 Fe{sub 2}O{sub 3} and 5-nm Au nanocrystals, 12.6-nm Fe{sub 3}O{sub 4} 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 (3{sup 3}.4{sup 2}) Archimedean tiling as the 'wetting layer' between the periodic and aperiodic phases.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); NSF MRSEC
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 967947
- Report Number(s):
- ANL/CNM/JA-64638; TRN: US200924%%58
- Journal Information:
- Nature, Vol. 461, Issue Oct. 15, 2009
- Country of Publication:
- United States
- Language:
- ENGLISH
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