Chemical stability and degradation mechanisms of triangular Ag, Ag@Au, and Au nanoprisms

Abstract

Anisotropic metal nanoparticles have found use in a variety of plasmonic applications because of the large near-field enhancements associated with them; however, the very features that give rise to these enhancements (e.g., sharply curved edges and tips) often have high surface energies and are easily degraded. This paper describes the stability and degradation mechanisms of triangular silver, gold-coated silver, and gold nanoprisms upon exposure to a wide variety of adverse conditions, including halide ions, thiols, amines and elevated temperatures. The silver nanoprisms were immediately and irreversibly degraded under all of the conditions studied. In contrast, the core-shell Ag@Au nanoprisms were less susceptible to etching by chlorides and bromides, but were rapidly degraded by iodides, amines and thiols by a different degradation pathway. Only the pure gold nanoprisms were stable to all of the conditions tested. These results have important implications for the suitability of triangular nanoprisms in many applications; this is particularly true in biological or environmental fields, where the nanoparticles would inevitably be exposed to a wide variety of chemical stimuli.

Polyvinylpyrrolidone-induced anisotropic growth of gold nanoprisms in plasmon-driven synthesis

“…Gold (Au) nanostructures are anticipated to provide an ideal system for exploring the plasmon-mediated growth process; they exhibit similar crystallographic structures and plasmonic properties to Ag nanostructures, but boast superior resistance to both chemical oxidation and electron-beam damage [13][14][15][16] . A mechanistic investigation of these photochemical reactions in Au nanomaterials is therefore expected to lend fundamental insights into this process and inform a general description of plasmon-mediated nanocrystal growth.…”

Effect of Pore Size and Film Thickness on Gold-Coated Nanoporous Anodic Aluminum Oxide Substrates for Surface-Enhanced Raman Scattering Sensor

“…However, gold is biologically inert. It is chemically and environmentally a more stable plasmonic material than silver [ 26 , 27 ]. In order to make these substrates SERS active, the membranes are coated with gold film thicknesses ranging from 30 nm to 120 nm with a sputtering system, Denton Discovery 18.…”

“…We have seen that the substrates coated with gold layer remain unaffected for several months. While silver is known to provide a slight improvement in SERS efficiency, gold-coated substrates were used in this work for the following reasons: (1) the surface plasmon resonance for silver is generally at shorter wavelengths compared to gold [ 27 , 28 , 29 ] and so it will be less suitable for the 785 nm laser used in this work; (2) silver films oxidize relatively easier than gold and so has a more limited lifetime [ 26 , 27 ].…”

Silver Nanoplates for Colorimetric Determination of Xanthine in Human Plasma and in Fish Meat via Etching/Aggregation/Fusion Steps

“…Silver nanoplates (AgP) are anisotropic metal nanoparticles and have attracted interest due to their morphology-dependent plasmonic properties and tunable plasmonic bands throughout the visible to near-infrared region [ 11 , 12 ]. In addition, owing to the Gibbs–Thomson effect, the sharp tips are more reactive than the edges, which are easily etched by other molecules, making them ideal materials for sensing applications [ 12 , 13 ]. Wang et al reported a dual-read probe for colorimetric and fluorometric detection of uric acid-based AgP and carbon nanodots.…”