title: Assembly of colloidal semiconductor nanorods in solution by depletion attraction.
abstract: Arranging anisotropic nanoparticles into ordered assemblies remains a challenging quest requiring innovative and ingenuous approaches. The variety of interactions present in colloidal solutions of nonspherical inorganic nanocrystals can be exploited for this purpose. By tuning depletion attraction forces between hydrophobic colloidal nanorods of semiconductors, dispersed in an organic solvent, these could be assembled into 2D monolayers of close-packed hexagonally ordered arrays directly in solution. Once formed, these layers could be fished onto a substrate, and sheets of vertically standing rods were fabricated, with no additional external bias applied. Alternatively, the assemblies could be isolated and redispersed in polar solvents, yielding suspensions of micrometer-sized sheets which could be chemically treated directly in solution. Depletion attraction forces were also effective in the shape-selective separation of nanorods from binary mixtures of rods and spheres. The reported procedures have the potential to enable powerful and cost-effective fabrication approaches to materials and devices based on self-organized anisotropic nanoparticles.
authors.affiliation: Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Baranov
authors.forename: Angela
authors.initials: A
authors.lastname: Fiore
authors.forename: Marijn
authors.initials: M
authors.lastname: van Huis
authors.forename: Cinzia
authors.initials: C
authors.lastname: Giannini
authors.forename: Andrea
authors.initials: A
authors.lastname: Falqui
authors.forename: Ugo
authors.initials: U
authors.lastname: Lafont
authors.forename: Henny
authors.initials: H
authors.lastname: Zandbergen
authors.forename: Marco
authors.initials: M
authors.lastname: Zanella
authors.forename: Roberto
authors.initials: R
authors.lastname: Cingolani
authors.forename: Liberato
authors.initials: L
authors.lastname: Manna
mesh_terms: D016880:Anisotropy; D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D012666:Semiconductors; D012997:Solvents / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D003102:Colloids; D012997:Solvents