title: Highly stable silica-coated gold nanorods dimers for solution-based SERS.
abstract: The controlled assembly of anisotropic plasmonic nanoparticles (NPs) into highly SERS-active substrates remains particularly challenging for the production of long-term stable NP assemblies in suspension. In this work, we report a simple and efficient strategy to assemble gold nanorods (AuNRs) into dimers. The pH-dependent assembly was triggered using the bifunctional molecular linker BPE (1,2-bis(4-pyridyl)ethylene) and quenched with silver nitrate. The resulting AuNR dimers were encapsulated in mesoporous silica shell and proved to be stable in water for at least 5 months. Taking advantage of the large Raman scattering cross-section of the linker BPE, we conducted a detailed study of the enhancement ability of these NR dimers using solution-based surface enhanced Raman scattering (SERS). Both experimental (SERS) and theoretical (discrete dipole approximation) studies of the near-field characteristics revealed a two-orders of magnitude increase of the SERS enhancement factor for the dimers as compared to isolated AuNRs. Besides thermal and colloidal stability, mesoporous silica coating of AuNRs imparts other notable advantages due to its porosity and biocompatibility, which make these core-shell plasmonic platforms promising for future bio-applications.
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Israa
authors.initials: I
authors.lastname: Haidar
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Georges
authors.initials: G
authors.lastname: Lévi
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Mouton
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Jean
authors.initials: J
authors.lastname: Aubard
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Johan
authors.initials: J
authors.lastname: Grand
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lau-Truong
authors.affiliation: IPGP-CNRS, Sorbonne Paris Cité, 1 rue Jussieu, 75238 Paris Cedex 05, France.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Neuville
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Nordin
authors.initials: N
authors.lastname: Félidj
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. leila.boubekeur@univ-paris-diderot.fr.
authors.forename: Leïla
authors.initials: L
authors.lastname: Boubekeur-Lecaque