title: Spray-assisted alignment of Layer-by-Layer assembled silver nanowires: a general approach for the preparation of highly anisotropic nano-composite films.
abstract: The present article focuses on the build-up and the properties of oriented silver nanowire monolayer films and Layer-by-Layer assembled multilayer films. We describe the template-free oriented spray-assisted assembly of silver nanowires at solid/air-interfaces using Grazing Incidence Spraying, a simple and versatile approach that allows the formation of highly oriented thin films with a tunable density and in-plane orientation. Depending on the spraying conditions the nematic order parameter, which describes the angular spread of misaligned nanowires, can be as high as 0.98 (a value of 1.00 corresponding to a perfectly parallel alignment). The combination with the Layer-by-Layer assembly allows building multilayer thin films possessing in-plane anisotropy. In order to demonstrate that the local alignment does not cancel out on the macroscopic scale but leads to direction-dependent properties, we use linearly polarized UV-Vis-NIR spectroscopy to probe the selective excitation of the transverse and longitudinal localized plasmon resonances of the nanowires. The polarization efficiency of the thin films increases strongly with the in-plane density, the degree of orientation, and the number of silver nanowire layers. Multilayer films containing 4 layers of nanowires oriented in the same direction reach a polarization efficiency of up to 97% in the near-infrared region.
authors.affiliation: Institut Charles Sadron, CNRS (UPR22), 23 rue du Loess, F-67034 Strasbourg, France. matthias.pauly@ics-cnrs.unistra.fr decher@unistra.fr.
authors.forename: H
authors.initials: H
authors.lastname: Hu
authors.affiliation: Institut Charles Sadron, CNRS (UPR22), 23 rue du Loess, F-67034 Strasbourg, France. matthias.pauly@ics-cnrs.unistra.fr decher@unistra.fr and Faculté de Chimie, Université de Strasbourg, 1 rue Blaise Pascal, F-67008 Strasbourg, France.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-7492-0710
authors.initials: M
authors.lastname: Pauly
authors.affiliation: Institut Charles Sadron, CNRS (UPR22), 23 rue du Loess, F-67034 Strasbourg, France. matthias.pauly@ics-cnrs.unistra.fr decher@unistra.fr.
authors.forename: O
authors.initials: O
authors.lastname: Felix
authors.affiliation: Institut Charles Sadron, CNRS (UPR22), 23 rue du Loess, F-67034 Strasbourg, France. matthias.pauly@ics-cnrs.unistra.fr decher@unistra.fr and Faculté de Chimie, Université de Strasbourg, 1 rue Blaise Pascal, F-67008 Strasbourg, France and International Center for Frontier Research in Chemistry, 8 allée Gaspard Monge, F-67083 Strasbourg, France and Excellence Cluster "Nanostructures in Interaction with their Environment" (LabEx NIE), 23 rue du Loess, F-67034 Strasbourg, France.
authors.forename: G
authors.initials: G
authors.lastname: Decher