title: Free-standing nanoparticle superlattice sheets controlled by DNA.
abstract: Free-standing nanoparticle superlattices (suspended highly ordered nanoparticle arrays) are ideal for designing metamaterials and nanodevices free of substrate-induced electromagnetic interference. Here, we report on the first DNA-based route towards monolayered free-standing nanoparticle superlattices. In an unconventional way, DNA was used as a 'dry ligand' in a microhole-confined, drying-mediated self-assembly process. Without the requirement of specific Watson-Crick base-pairing, we obtained discrete, free-standing superlattice sheets in which both structure (inter-particle spacings) and functional properties (plasmonic and mechanical) can be rationally controlled by adjusting DNA length. In particular, the edge-to-edge inter-particle spacing for monolayered superlattice sheets can be tuned up to 20 nm, which is a much wider range than has been achieved with alkyl molecular ligands. Our method opens a simple yet efficient avenue towards the assembly of artificial nanoparticle solids in their ultimate thickness limit--a promising step that may enable the integration of free-standing superlattices into solid-state nanodevices.
authors.affiliation: Department of Biological & Environmental Engineering, Cornell University, 226 Riley Robb, Ithaca, New York 14853, USA.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Cheng
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Campolongo
authors.forename: Judy J
authors.initials: JJ
authors.lastname: Cha
authors.forename: Shawn J
authors.initials: SJ
authors.lastname: Tan
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Umbach
authors.forename: David A
authors.initials: DA
authors.lastname: Muller
authors.forename: Dan
authors.initials: D
authors.lastname: Luo
mesh_terms: D004247:DNA / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles
chemical_list: D004247:DNA