Colloidal crystal ordering in a liquid crystal

Nanoparticles (NPs) can now be synthesized with a wide array of controlled sizes, shapes, and properties. However, turning them into nanomaterials often requires packing them into ordered assemblies to manifest specific electronic or optical properties for applications in nanoelectronics, optics, and metamaterials. Colloidal self-assembly ( 1 ) of NPs is relatively simple but is often restricted to high-symmetry crystals by the lack of specific directional bonds, especially for dilute NP solutions. To obtain lower symmetries that confer useful optical or electronic properties, long-range directional interactions must be imparted. On page 69 of this issue, Mundoor et al. ( 2 ) make clever use of an anisotropic host fluid, a liquid crystal, to promote the formation of a low-symmetry crystal in a dilute dispersion of nanorods.