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Colloquium | Nanoscience and Technology Division

Chiral Plasmonic Nanomaterials by Templated Growth and Assembly of Gold Nanocrystals

NST Colloquium

Abstract: The field of chirality has seen a strong rejuvenation due to the observation of nanoscale chirality in plasmonic nanoparticles. This lecture will highlight recent advances in the field of plasmonic chirality, including novel methods for the synthesis of optically active plasmonic nanomaterials. The focus will be first directed toward chiral nano-structures formed using biological templates, proteins in particular. After demonstration of the directed self-assembly of gold nanorods on amyloid fibers, as well as the mechanistic understanding of chirality at the nanoscale, a potential application for such nanomaterials will be presented. We propose that plasmon-enhanced chiral signals have great potential for use in the detection and therapy of neurodegenerative disorders.

The second part of the lecture will deal with the seeded-growth of chiral features on colloidal nanoparticles. A novel approach will be introduced, comprising the self-organization of surfactant micelles into chiral structures on nanoparticle seeds. This simple concept opens a wide range of possibilities, by playing around with the huge variety of chiral co-surfactants, seed morphologies and metal compositions, which have been studied in the context of the seeded-growth of metal nanoparticles. We demonstrate that the addition of chiral co-surfactants leads to supramolecular interactions with CTAC, resulting in chiral helices that can wrap gold nanocrystals and template the seeded growth into chiral features. The resulting chiral nanoparticle colloids display high morphological and optical handedness, which can be tuned through the visible and the near IR. This approach provides a reproducible, simple and scalable method toward the fabrication of nanoparticles with high chiral optical activity.