Issue 45, 2022

Asymmetric seed passivation for regioselective overgrowth and formation of plasmonic nanobowls

Abstract

Plasmonic nanoparticles (NPs) have garnered excitement over the past several decades stemming from their unique optoelectronic properties, leading to their use in various sensing applications and theranostics. Symmetry dictates the properties of many nanomaterials, and nanostructures with low, but still defined symmetries, often display markedly different properties compared to their higher symmetry counterparts. While numerous methods are available to manipulate symmetry, surface protecting groups such as polymers are finding use due to their ability to achieve regioselective modification of NP seeds, which can be removed after overgrowth as shown here. Specifically, poly(styrene-b-polyacrylic acid) (PSPAA) is used to asymmetrically passivate cubic Au seeds through competition with hexadecyltrimethylammonium bromide (CTAB) ligands. The asymmetric passivation via collapsed PSPAA causes only select vertices and faces of the Au cubes to be available for deposition of new material (i.e., Au, Au–Ag alloy, and Au–Pd alloy) during seeded overgrowth. At low metal precursor concentrations, deposition follows observations from unpassivated seeds but with new material growing from only the exposed seed portions. At high metal precursor concentrations, nanobowl-like structures form from interaction between the depositing phase and the passivating PSPAA. Through experiment and simulation, the optoelectronic properties of these nanobowls were probed, finding that the interiors and exteriors of the nanobowls can be functionalized selectively as revealed by surface enhanced Raman spectroscopy (SERS).

Graphical abstract: Asymmetric seed passivation for regioselective overgrowth and formation of plasmonic nanobowls

Supplementary files

Article information

Article type
Paper
Submitted
20 9 2022
Accepted
31 10 2022
First published
08 11 2022
This article is Open Access
Creative Commons BY license

Nanoscale, 2022,14, 16918-16928

Asymmetric seed passivation for regioselective overgrowth and formation of plasmonic nanobowls

Z. J. Woessner, G. R. Lewis, S. L. A. Bueno, E. Ringe and S. E. Skrabalak, Nanoscale, 2022, 14, 16918 DOI: 10.1039/D2NR05182F

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