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.

Nanoparticle Superlattices: The Roles of Soft Ligands

“…Attaching biomolecules such as DNA,11, 46, 47, 135 proteins136, 137, 138, 139, 140 and antibodies141, 142 to nanoparticle surfaces offer a unique specific route to control their assembly. Such assemblies are attractive because they can be programmed into complex structures, such as chiral architectures 141.…”

“…The charge carrier transport across polymer‐ or DNA‐based superlattices has yet to be reported, possibly due to the large interparticle spacing. Nevertheless, the spacing is still within strong plasmonic coupling range 11, 12, 49. Tunable plasmonic properties of both polymer‐ and DNA‐based superlattices have been demonstrated previously.…”

“…In some cases, unprecedented lattice structures could be obtained 21. Some of these superlattices are robust enough, allowing for investigating unusual mechanical, plasmonic, conducting properties from superlattice assemblies 3, 5, 11, 12…”

“…For instance, Coherent vibrational modes can only appear in highly ordered nanoparticle superlattices,3 and synergistic effects in superlattices can lead to enhanced p‐type conductivity;5 2D DNA‐metal nanoparticle sheets exhibited unusual mechanical properties;11 2D polymer‐nanorod superlattice sheets exhibited novel plasmonic properties dependent on packing order 12 …”

“…Reproduced with permission 10, 11, 12, 18, 20, 21, 79, 120, 133, 135, 138, 144, 171, 172, 173, 174, 175, 176, 177. Copyright 1998, 2001, 2006, 2007, 2009, 2010, 2011, 2013, Nature Publishing Group.…”