AMADEus Seminar - Dr. Leïla Boubekeur-Lecaque - Tuesday 4 december 2018 - 11:00 am -ICMCB (Amphi)

Surface-enhanced Raman scattering (SERS) has become a major vibrational spectroscopic technique moving fast towards areas of biology, forensic science, analytical chemistry, art and conservation science.¹ SERS relies on a giant enhancement of the Raman intensity recorded for molecules located in the vicinity of the surface of metallic nanostructures. The Raman enhancement in SERS, a million-fold higher than in Normal Raman, originates from the excitation of localized surface plasmons sustained by metallic nanoparticles.² These outstanding properties have stimulated a huge enthusiasm for the SERS process, for which the plasmonic nanostructures act as antennae for the molecules.
Our projects are devoted to the synthesis of metallic (Ag, Au) nanoparticles and their controlled assembly by bottom-up approach. In such colloidal assembly or aggregates, the enhancement originates mainly from specific local areas called “hot spots”, located within
gaps in colloidal aggregates. However, important issues related to poor reproducibility of highly SERS-active nanostructures in solution, and the lack of quantitative SERS signals, remain challenging for solution-based SERS. We will describe a facile and reproducible strategy developed in our group to assemble gold nanorods (AuNRs) into dimers in solution.^3,4 The benefits of the resulting coupled gold nanorods in terms of stability and field enhancement were assessed by SERS. In a second part, we will demonstrate how the combination of SERS with other characterization techniques has contributed to establishing the key parameters that govern the growth mechanism of anisotropic core-shell Au@Ag nanoparticles.^5,6

CONTACTS:
CBMN: Emilie Pouget, e.pouget@cbmn.u-bordeaux.fr
ICMCB : Mona Treguer-Delapierre, Mona.Treguer@icmcb.cnrs.fr

[1] Le Ru, E. C.; Etchegoin, P. G., Principles of Surface-Enhanced Raman Spectroscopy and Related Plasmonic Effects; Elsevier:Oxford, 2009
[2] Boubekeur-Lecaque, L.; Félidj, N.; Lamy de la Chapelle, M. ; Photoniques 2018 (90), 41–44
[3] Haidar, I.; Aubard, J.; Levi, G.; Lau Truong, S.; Mouton, L.; Neuville, D.; Felidj, N.; Boubekeur-Lecaque, L. J. Phys. Chem. C 2015, 119, 23149-23158
[4] Haidar, I.; Levi, G.; Mouton, L.; Aubard, J.; Lau-Truong, S.; Grand, j.; Neuville, D. R.; Felidj, N.; Boubekeur-Lecaque, L., Phys.Chem. Chem. Phys. 2016, 18, 32272-32280
[5] Haidar, I. ; Day, A. ; Decorse, P. ; Lau-Truong, S. ; Chevillot-Biraud, A. ; Aubard, J. ; Félidj, N. ; Boubekeur-Lecaque, L. ; « Tailoring the Shape of Anisotropic Core-Shell Au-Ag Nanoparticles », submitted
[6] Boubekeur-Lecaque, L.; Haidar, I.; Félidj, N.; Neuville, D. R.; WO2018069646 (2016)