Tic-Tac-Toe Binary Lattices from the Interfacial Self-Assembly of Branched and Spherical Nanocrystals

Andrea Castelli, Joost de Graaf, Mirko Prato, Liberato Manna, Milena P. Arciniegas

Research output: Contribution to journalArticlepeer-review

Abstract

The self-organization of nanocrystals has proven to be a versatile route to achieve increasingly sophisticated structures of materials, where the shape and properties of individual particles impact the final functionalities. Recent works have addressed this topic by combining various shapes to achieve more complex arrangements of particles than are possible in single component samples. However, the ability to create intricate architectures over large regions by exploiting the shape of multiply branched nanocrystals to host a second component remains unexplored. Here, we show how the concave shape of a branched nanocrystal, the so-called octapod, is able to anchor a sphere. The two components self-assemble into a locally ordered monolayer consisting of an intercalated square lattice of octapods and spheres, which is reminiscent of the "tic-tac-toe" game. These tic-tac-toe domains form through an interfacial self-assembly that occurs by the dewetting of a hexane layer containing both particle types. By varying the experimental conditions and performing molecular dynamics simulations, we show that the ligands coating the octapods are crucial to the formation of this structure. We find that the tendency of an octapod to form an interlocking-type structure with a second octapod strongly depends on the ligand shell of the pods. Breaking this tendency by ligand exchange allows the octapods to assemble into a more relaxed configuration, which is able to form a lock-and-key-type structure with a sphere, when they have a suitable size ratio. Our findings provide an example of a more versatile use of branched nanocrystals in self-assembled functional materials.

Original languageEnglish
Pages (from-to)4345-4353
Number of pages9
JournalACS Nano
Volume10
Issue number4
DOIs
Publication statusPublished - 30 Mar 2016

Keywords

  • interfacial self-assembly
  • octapods
  • spheres
  • ligand exchange
  • binary superlattice
  • COLLOIDAL NANOCRYSTALS
  • NANOPARTICLE SUPERLATTICES
  • STRUCTURAL DIVERSITY
  • BUILDING-BLOCKS
  • SEEDED GROWTH
  • SHAPE
  • CDSE
  • PATCHINESS
  • ATTACHMENT
  • NANORODS

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