Many properties of materials depend on their structural symmetry—for example, piezoelectricity is simply not observed in high-symmetry configurations. When the building blocks of a lattice are isotropic (perfectly uniform), they rarely form a low-symmetry crystal system. Now, by controlling the interlinking of isotropic nanoparticles, it is possible to custom-design the symmetry of a self-assembled lattice and enhance the desired properties in the full nanomaterial.
Lattice Design via Multivalent Linkers (LDML) is based on specially synthesized linkers with multiple attachment points, which determine connections between isotropic DNA-coated particles. Such linkers possess a specific symmetry that, analogously to atomic bonds, will result in the formed lattice displaying a designed symmetry. By introducing linkers with a specific architecture of linker-particle connecting sites determined by molecular bonds (for example DNA, hydrogen bonds etc.), the correspondence between linker symmetry and packing of particles into superstructures emerges during the self-assembly process.
Applications and Industries
These techniques can be used to self-assemble nanoparticle lattices with arbitrary symmetry from isotropic building blocks, resulting in unique optical, electrical, magnetic, and structural properties for individual devices or extended networks. The applications range from large-scale industrial processes to consumer electronics.
Metamaterials exhibit properties not seen in naturally occurring materials, such as negative index of refraction, in part because of their crystal symmetries. By self-assembling nanoparticles into lattices displaying chosen symmetries, it is possible to custom-design the properties of the metamaterials without resorting to top-down processing methods. The self-assembly method is straightforward and particularly well suited to prototyping, whereas nanoscale lithography is quite expensive and complex to implement.