Colloidal Crystals: Using Self-Assembly to Create Structures From Nanoparticle Building Blocks

Today, the creation of new functional materials remains an empirically driven process. Designing materials for future technologies will require some element of predictability and could be realized through a modular approach in which nanoparticles (NPs) are used as building blocks to assemble materials with specific properties. In this article, we consider how the self-assembly of NPs into colloidal crystals with long-range order can be achieved and the factors driving NP assembly. First, we examine binary NP superlattices as a self-assembled system in which a huge diversity of structures with different symmetries and stoichiometries can be found; second, we review how deoxyribonucleic acid can be used to improve the control with which NPs can be self-assembled; and finally, we describe how photonic crystals can be formed using templated self-assembly processes as an example of the potential applications of self-assembled colloidal crystals. While most systems explored to date employ static self-assembly processes, they point to the future possibility of responsive self-assembly approaches for designing smart materials that can be controlled by external energy input. Ultimately, improving our understanding of self-assembly will permit the formation of large-scale NP assemblies and lead to considerable improvements in the rational design of novel materials with new and exciting properties.