Enabling Hierarchical Material Structures by Integrating DNA-Programmed Nanoscale Assembly with Macroscopic Processing Methods

The programmability of DNA makes it an attractive structure-directing ligand for the assembly of nanoparticle superlattices with unique structure-dependent physical phenomena. Grafting a dense brush of synthetic DNA strands to the surface of a nanoparticle allows the predictable nature of Watson-Crick base pairing to define the strength and specificity of interparticle binding. As a result, nanoparticles can be intentionally assembled into superlattices nanometer-scale precision in nanoparticle placement and independent control over particle size, lattice parameters, and crystal symmetry. However, although DNA hybridization allows particles to easily adopt arrangements that maximize nearest-neighbor bonding, it provides no intrinsic means of controlling structural factors at length scales beyond the local coordination environment around individual particles, and thus manipulating the macroscopic shape of the lattices remains challenging. Because of this limitation, the measurement of specific properties or fabrication of devices enabled by these structures remain underexplored areas compared to advancements in their synthesis. In this talk, we will demonstrate how external fields or physical forces can enable the precise placement of faceted single-crystal superlattices across square centimeter areas. We will also show how the programmability of DNA tailors the hierarchical mechanical and optical properties of nanoparticle assemblies, and demonstrate one of the first examples of a DNA-nanoparticle superlattice device. Finally, we will demonstrate how light can be used to drive nanoparticle assembly via localized plasmon-driven heating, creating mm-sized crystals of arbitrary shapes at speeds 100x greater than standard assembly methods. Together, these experiments show that fundamental scientific understanding of nanoscale assembly with DNA results in a powerful tool for the synthesis of complex hierarchical structures with beneficial physical characteristics for device engineering.