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Published August 10, 2014 | public
Journal Article

Stepwise and epitaxial growth of DNA-programmable nanoparticle superlattices

Abstract

Many researchers are interested in developing methods for rationally assembling nanoparticle building blocks into periodic lattices. These superlattices could in principle be used to create designer materials with unique properties, useful in optics, biomedicine, energy, and catalysis. DNA is a particularly attractive ligand for the programmable assembly of nanoparticles, as synthetically tunable variations in nucleotide sequence allow for precise engineering of the nanoparticle hydrodynamic radius and hybridization properties. These factors, in turn, dictate the crystallog. symmetry and lattice parameter of the assembly. Although superlattices with diverse geometries can be assembled in soln., the incorporation of specific bonding interactions between particle building blocks and a substrate would significantly enhance control over the crystal growth process. Herein, we use a stepwise growth process to systematically study and control the evolution of a bcc cryst. thin-film comprised of DNA-functionalized nanoparticle building blocks on a complementary DNA substrate. We examine crystal growth as a function of temp., no. of layers, and substrate-particle bonding interactions. Importantly, the judicious choice of DNA interconnects allows one to tune the interfacial energy between various crystal planes and the substrate, and thereby control crystal orientation and size in a stepwise fashion using chem. programmable attractive forces. We further demonstrate that such assemblies can be grown epitaxially on lithog. patterned templates, eliminating grain boundaries and enabling fine control over orientation and size of assemblies up to thousands of square micrometers. The effects of drying on the superlattice structure are examd.; surprisingly, this allows for a reversible contraction and expansion of the colloidal crystal with a greater than 60% decrease in the vol. of the lattice. Ultimately, this work will be important for the development of on-chip material platforms that take advantage of the periodicity and/or controlled d. of the inorg. core, such as optical metamaterials, photonic crystals and heterogeneous catalysts.

Additional Information

© 2014 American Chemical Society.

Additional details

Created:
August 20, 2023
Modified:
October 20, 2023