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SUMMARY:Coupled and Chiral Surface Plasmons in Metal Nanostructures
DTSTART:20120827T110000
DTSTAMP:20260407T002552Z
UID:aa6e57bfa60191ea0c3193b0066b9b5e96a1f2679c8e7f0b67d80fb6
CATEGORIES:Conferences - Seminars
DESCRIPTION:K. George Thomas\, Indian Institute of Science Education and R
 esearch\nThe presentation will provide examples of modulating the optical 
 properties of nanomaterials by integrating them into higher order assembli
 es using electrostatic\, supramolecular and covalent approaches. Various a
 pproaches to organize metal nanoparticles by varying the distance and geom
 etry will be discussed in the first part of the presentation\, highlightin
 g the role of plasmon coupling and SERS. Raman signal enhancement of diffe
 rent analyte molecules\, when placed at various locations of these assembl
 ies (such as junctions and edges) will be presented. Enhancement of Raman 
 signals of pyrene molecule due to the enhanced electric fields on the surf
 ace of silver nanoparticles\, by controlling the thickness of silica shell
 \, will be discussed. Dimeric nanostructures having well defined gap betwe
 en two silver nanoparticles were prepared and the gap size was varied from
  1.5 – 40 nm. The experimental Raman enhancement factors at the hot spot
  follow a 1/dn dependence with n = 1.5\, in agreement with the recent theo
 retical studies by Schatz and co-workers. In the second part of the presen
 tation\, a novel strategy for inducing chirality to metal nanoparticles\, 
 by growing them on peptide nanotube surfaces will be discussed. The surfac
 e plasmon coupled circular dichroism in these systems originates from the 
 asymmetric organization of Au nanoparticles\, resulting in bisignated CD s
 ignals. The chiral information and asymmetry at the molecular level on the
  D- and L-isomers of peptide nanotubes are transferred to gold nanoparticl
 es.
LOCATION:MXF 1 https://plan.epfl.ch/?room==MXF%201
STATUS:CONFIRMED
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