Quantitative 3D real-space analysis of Laves phase supraparticles.

Assembling binary mixtures of nanoparticles into crystals, gives rise to collective properties depending on the crystal structure and the individual properties of both species. However, quantitative 3D real-space analysis of binary colloidal crystals with a thickness of more than 10 layers of particles has rarely been performed. Here we demonstrate that an excess of one species in the binary nanoparticle mixture suppresses the formation of icosahedral order in the self-assembly in droplets, allowing the study of bulk-like binary crystal structures with a spherical morphology also called supraparticles.

Tuning the Glass Transition: Enhanced Crystallization of the Laves Phases in Nearly Hard Spheres.

Colloidal crystals with a diamond and pyrochlore structure display wide photonic band gaps at low refractive index contrasts. However, these low-coordinated and open structures are notoriously difficult to self-assemble from colloids interacting with simple pair interactions. To circumvent these problems, one can self-assemble both structures in a closely packed MgCu Laves phase from a binary mixture of colloidal spheres and then selectively remove one of the sublattices.

Crystallization of Nanocrystals in Spherical Confinement Probed by in Situ X-ray Scattering.

We studied the formation of supraparticles from nanocrystals confined in slowly evaporating oil droplets in an oil-in-water emulsion. The nanocrystals consist of an FeO core, a CoFeO shell, and oleate capping ligands, with an overall diameter of 12.5 nm.

Towards the colloidal Laves phase from binary hard-sphere mixtures via sedimentation.

Colloidal photonic crystals, which show a complete band gap in the visible region, have numerous applications in fibre optics, energy storage and conversion, and optical wave guides. Intriguingly, two of the best examples of photonic crystals, the diamond and pyrochlore structure, can be self-assembled into the colloidal MgCu2 Laves phase crystal from a simple binary hard-sphere mixture. For these colloidal length scales thermal and gravitational energies are often comparable and therefore it is worthwhile to study the sedimentation phase behavior of these systems.

Fabrication of Colloidal Laves Phases via Hard Tetramers and Hard Spheres: Bulk Phase Diagram and Sedimentation Behavior.

Colloidal photonic crystals display peculiar optical properties that make them particularly suitable for application in different fields. However, the low packing fraction of the targeted structures usually poses a real challenge in the fabrication stage. Here, we propose a route to colloidal photonic crystals via a binary mixture of hard tetramers and hard spheres.

Growth of defect-free colloidal hard-sphere crystals using colloidal epitaxy.

Using event-driven Brownian dynamics simulations, we investigate the epitaxial growth of hard-sphere crystals with a face-centered-cubic (fcc) structure on the three densest cross-sectional planes of the fcc: (i) fcc (100), (ii) fcc (111), and (iii) fcc (110). We observe that for high settling velocities, large fcc crystals with very few extended defects grow on the fcc (100) template. Our results show good agreement with the experiments of Jensen et al.

Stabilizing the hexagonal close packed structure of hard spheres with polymers: Phase diagram, structure, and dynamics.

We study the phase behaviour of a binary mixture of colloidal hard spheres and freely jointed chains of beads using Monte Carlo simulations. Recently Panagiotopoulos and co-workers predicted [Nat. Commun.