Optomechanical Hot-Spots in Metallic Nanorod–Polymer Nanocomposites

Abstract

Plasmonic coupling between adjacent metallic nanoparticles can be exploited for acousto-plasmonics, single-molecule sensing, and photochemistry. Light absorption or electron probes can be used to study plasmons and their interactions, but their use is challenging for disordered systems and colloids dispersed in insulating matrices. Here, we investigate the effect of plasmonic coupling on optomechanics with Brillouin light spectroscopy (BLS) in a prototypical metal−polymer nanocomposite, gold nanorods (Au NRs) in polyvinyl alcohol. The intensity of the light inelastically scattered on thermal phonons captured by BLS is strongly affected by the wavelength of the probing light. When light is resonant with the transverse plasmons, BLS reveals mostly the normal vibrational modes of single NRs. For lower energy off-resonant light, BLS is dominated by coupled bending modes of NR dimers. The experimental results, supported by optomechanical calculations, document plasmonically enhanced BLS and reveal energy-dependent confinement of coupled plasmons close to the tips of NR dimers, generating BLS hot-spots. Our work establishes BLS as an optomechanical probe of plasmons and promotes nanorod− soft matter nanocomposites for acousto-plasmonic applications.

Sensitivity of Localized Surface Plasmon Resonance and Acoustic Vibrations to Edge Rounding in Silver Nanocubes

“…It originates mainly from the cubic structure of the lattice. This splitting of the most intense Raman peak due to the cubic lattice structure has recently been confirmed by calculating the Raman intensities. , This attests that most of the NCBs studied in this work have a single-crystal structure, as shown by the HRTEM analysis. Based on previous calculations, the band centered slightly below 1000 m s –1 is unambiguously assigned to the lowest frequency E g mode of Ag NCBs, while the one around 1500 m s –1 is attributed to acoustic vibrations with the T 2 g irreducible representation.…”

“…Scattering by additional modes occurs when the internanoparticle electromagnetic interaction increases (i.e., for decreasing values of the ratio of the internanocube distance to the size of the Extension of this work to analyze the dependence of the inelastic light scattering signal recorded from rounded nanocubes upon change of the excitation wavelength will be of great interest for studying the acousto-plasmonic interaction in such nanoobjects. Experimental data on this subject would support in particular the recent development of numerical models to calculate the Raman intensity 73,74 for nonspherical elastically anisotropic nanoparticles.…”

Understanding the Photothermal and Photocatalytic Mechanism of Polydopamine Coated Gold Nanorods

“…It is important to remember that in the actual samples, aggregation can lead to an asymmetric broadening of the transverse plasmon resonance to longer wavelengths (see Figure 1g) and a blueshift of the longitudinal plasmons. [ 55 ] Taking aggregation also into account, it is expected to eliminate any significant mismatch between theory and experiment.…”

High-Resolution Tracking of Multiple Distributions in Metallic Nanostructures: Advanced Analysis Was Carried Out with Novel 3D Correlation Thermal Field-Flow Fractionation

“…Less rigorous and sustainable methodologies are critical for engineering advanced metal–polymer nanostructures with applications in energy storage and electronics; accordingly, it is necessary to combine separation and advanced analytical techniques for reliable characterizations of the inherent molecular heterogeneities. , Metallic nanostructures have multiple applications in energy storage, biosensors, drug delivery, wearable electronics, and robotics, to mention just a few. , However, these metallic nanostructures are inherently complex and heterogeneous, with multiple distributions in their molecular properties . As such, combinations of separation and advanced analytical techniques are prerequisites for the reliable definition, understanding, and fine-tuning of the fundamental nexus between (i) inherent molecular properties, (ii) physicochemical properties and multiple functionalities, and (iii) the pristine end-use applications …”

“…Less rigorous and sustainable methodologies are critical for engineering advanced metal−polymer nanostructures with applications in energy storage and electronics; accordingly, it is necessary to combine separation and advanced analytical techniques for reliable characterizations of the inherent molecular heterogeneities. 1,2 Metallic nanostructures have multiple applications in energy storage, biosensors, drug delivery, wearable electronics, and robotics, to mention just a few. 3,4 However, these metallic nanostructures are inherently complex and heterogeneous, with multiple distributions in their molecular properties.…”