Layer-by-Layer Growth of Binary Colloidal Crystals

Abstract

We report the growth of binary colloidal crystals with control over the crystal orientation through a simple layer-by-layer process. Well-ordered single binary colloidal crystals with a stoichiometry of large (L) and small (S) particles of LS2 and LS were generated. In addition, we observed the formation of an LS3 superstructure. The structures formed as a result of the templating effect of the first layer and the forces exerted by the surface tension of the drying liquid. By using spheres of different composition, one component can be selectively removed, as is demonstrated in the growth of a hexagonal non-close-packed colloidal crystal.

Colloids with valence and specific directional bonding

“…Because the self-assembly of these particles is largely controlled by their geometry, only a few relatively simple crystals have been made: face-centered and body-centered cubic crystals and variants 9 . Colloidal alloys increase the diversity of structures [10][11][12] , but many structures remain difficult or impossible to make. For example, the diamond lattice, predicted more than 20 years ago to have a full 3-dimensional photonic band gap 13 , still cannot be made by colloidal self-assembly because it requires 4-fold coordination.…”

Self-assembly of three-dimensional open structures using patchy colloidal particles

“…Various designs have been proposed [15][16][17][18][19][20][21], which require complicated inter-particle potentials that are difficult to realize in experiment.…”

Surface Patterning with Colloidal Monolayers

“…The creation of binary colloidal monolayers was pioneered by the group of von Blaaderen [104] who realized that close-packed monolayer of large spheres could be used as substrate in a controlled evaporation process to deposit small spheres on top of the monolayer to form binary crystals. During the evaporation process, the interstitial sites of the template monolayer act as traps for the small spheres that subsequently assemble into a regular superlattice on the large- Binary colloidal monolayers by a sequential convective assembly of small particles in the interstitial sites of a close-packed monolayer of large particles.…”

“…During the evaporation process, the interstitial sites of the template monolayer act as traps for the small spheres that subsequently assemble into a regular superlattice on the large- Binary colloidal monolayers by a sequential convective assembly of small particles in the interstitial sites of a close-packed monolayer of large particles. Scheme taken from Velikov et al [104] Depending on the concentration of the dispersion of small spheres, different configuration can be achieved.…”

“…They hold promise to be used not only in lithography -with the possibility to create nanostructures not readily available from single-sized particle monolayers -but in several distinct research areas such as crystal surface mimics [104,220] and quasi-crystallinity [221] or, when stacked into layered superstructures, photonic applications aiming at the generation of full photonic bandgap materials. [54,222] One even might envision more complex applications, e.g.…”