title: Defect tolerance and the effect of structural inhomogeneity in plasmonic DNA-nanoparticle superlattices.
abstract: Bottom-up assemblies of plasmonic nanoparticles exhibit unique optical effects such as tunable reflection, optical cavity modes, and tunable photonic resonances. Here, we compare detailed simulations with experiment to explore the effect of structural inhomogeneity on the optical response in DNA-gold nanoparticle superlattices. In particular, we explore the effect of background environment, nanoparticle polydispersity (>10%), and variation in nanoparticle placement (∼5%). At volume fractions less than 20% Au, the optical response is insensitive to particle size, defects, and inhomogeneity in the superlattice. At elevated volume fractions (20% and 25%), structures incorporating different sized nanoparticles (10-, 20-, and 40-nm diameter) each exhibit distinct far-field extinction and near-field properties. These optical properties are most pronounced in lattices with larger particles, which at fixed volume fraction have greater plasmonic coupling than those with smaller particles. Moreover, the incorporation of experimentally informed inhomogeneity leads to variation in far-field extinction and inconsistent electric-field intensities throughout the lattice, demonstrating that volume fraction is not sufficient to describe the optical properties of such structures. These data have important implications for understanding the role of particle and lattice inhomogeneity in determining the properties of plasmonic nanoparticle lattices with deliberately designed optical properties.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208; International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208;
authors.forename: Michael B
authors.initials: MB
authors.lastname: Ross
authors.affiliation: International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208; Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208.
authors.forename: Jessie C
authors.initials: JC
authors.lastname: Ku
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208; International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208;
authors.forename: Martin G
authors.initials: MG
authors.lastname: Blaber
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208; International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208; Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208 chadnano@northwestern.edu schatz@chem.northwestern.edu.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208; International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208; chadnano@northwestern.edu schatz@chem.northwestern.edu.
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
mesh_terms: D003198:Computer Simulation; D003460:Crystallization; D004247:DNA / Q000737:chemistry*; D004574:Electromagnetic Fields; D004581:Electronics; D006046:Gold / Q000737:chemistry; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry; D055095:Optics and Photonics; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry; D017356:Synchrotrons; D014965:X-Rays
chemical_list: D009841:Oligonucleotides; D006046:Gold; D012822:Silicon Dioxide; D004247:DNA
keywords: DNA; disorder; nanoparticle; noble metal; plasmonics