Shape Alloys of Nanorods and Nanospheres from Self-Assembly

Condensed Matter journal club

Shape Alloys of Nanorods and Nanospheres from Self-Assembly

  • Event time: 11:30am
  • Event date: 18th October 2013
  • Speaker: Tao Li (Formerly School of Physics & Astronomy, University of Edinburgh)
  • Location: Room 2511,

Event details

Abstract

Mixtures of anisotropic nanocrystals promise a great diversity of superlattices and phase behaviors beyond those of single-component systems. However, obtaining a colloidal shape alloy in which two different shapes are thermodynamically coassembled into a crystalline superlattice has remained a challenge. Here we present a joint experimental.computational investigation of two geometrically ubiquitous nanocrystalline building blocks - nanorods and nanospheres - that overcome their natural entropic tendency toward macroscopic phase separation and coassemble into three intriguing phases over centimeter scales, including an AB2-type binary superlattice. Monte Carlo simulations reveal that, although this shape alloy is entropically stable at high packing fraction, demixing is favored at experimental densities. Simulations with short-ranged attractive interactions demonstrate that the alloy is stabilized by interactions induced by ligand stabilizers and/or depletion effects. An asymmetry in the relative interaction strength between rods and spheres improves the robustness of the self-assembly process.
Nano Letters 13 4980-4988 (2013)
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Authors

Xingchen Ye, Jaime A Millan, Michael Engel, Jun Chen, Benjamin T Diroll, Sharon C Glotzer, Christopher B Murray