Colloidal Nanoantennas for Hyperspectral Chemical Mapping

Dill, Tyler J.; Rozin, Matthew J.; Palani, Stephen; Tao, Andrea R.

doi:10.1021/acsnano.6b02403

Cited by 17 publications

(10 citation statements)

References 42 publications

(72 reference statements)

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“…The resulting high concentrations of nonthermal electrons allow us to study their dynamics in great detail. Such a configuration was previously demonstrated in angle-insensitive perfect absorbers 20 , 21 , ultrafast emission sources 22 – 24 , single photon emitters 25 , and chemical sensors 26 , 27 . The use of colloidal silver nanocubes is a simple means of fabricating a conformal metasurface over large areas without the need for nanopatterning.…”

Section: Introductionmentioning

confidence: 92%

Enhanced generation and anisotropic Coulomb scattering of hot electrons in an ultra-broadband plasmonic nanopatch metasurface

et al. 2017

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The creation of energetic electrons through plasmon excitation of nanostructures before thermalization has been proposed for a wide number of applications in optical energy conversion and ultrafast nanophotonics. However, the use of “nonthermal” electrons is primarily limited by both a low generation efficiency and their ultrafast decay. We report experimental and theoretical results on the use of broadband plasmonic nanopatch metasurfaces comprising a gold substrate coupled to silver nanocubes that produce large concentrations of hot electrons, which we measure using transient absorption spectroscopy. We find evidence for three subpopulations of nonthermal carriers, which we propose arise from anisotropic electron–electron scattering within sp-bands near the Fermi surface. The bimetallic character of the metasurface strongly impacts the physics, with dissipation occurring primarily in the gold, whereas the quantum process of hot electron generation takes place in both components. Our calculations show that the choice of geometry and materials is crucial for producing strong ultrafast nonthermal electron components.

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Section: Introductionmentioning

confidence: 92%

Enhanced generation and anisotropic Coulomb scattering of hot electrons in an ultra-broadband plasmonic nanopatch metasurface

et al. 2017

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“…These methods (the mirror reaction, for instance) are convenient to produce metal coatings on nonconductive surfaces (SiO 2 , Si, …) . In addition, the deposition of a layer of colloidal Ag nanocubes by using a Langmuir–Blodgett method and that of spherical Au NPs on AFM tips were suggested as promising procedures to fabricate efficient tips for TERS imaging.…”

Section: Experimental Developments In Tersmentioning

confidence: 99%

Tip‐Enhanced Raman Spectroscopy: A Tool for Nanoscale Chemical and Structural Characterization of Biomolecules

Bonhommeau

Lecomte

2017

ChemPhysChem

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Due to its high molecular sensitivity and spatial optical resolution down to sub‐nanometer values, tip‐enhanced Raman spectroscopy (TERS) has emerged as a powerful microscopy technique for nanoscale characterization. Progress in TERS instrumentation and in the manufacturing of efficient TERS tips allow for chemical and structural analysis under various experimental conditions (different wavelengths, substrates, and surrounding media). Many biological species have been examined by using this technique. Nucleic acids (individual nucleobases, DNA, and RNA) can show specific TERS features that reveal their composition, conformation, and defects. TERS studies on peptides and proteins (such as amyloid fibrils) provide relevant information on their morphology and structure, leading to valuable insight to their functions and behavior. Finally, lipid layers and membranes, viruses, bacteria, and cells can also be finely characterized. Generalizing TERS measurements in liq‐ uid medium to study biological systems is the main future challenge.

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“…This is something that has been a typical issue for TERS. 28,29 Attention has as a result shifted towards tips based around colloidal noble metal nanoparticles, [30][31][32] the synthesis of which falls within the domain of 'bottom-up' nano-engineering. The shape, size and composition of such particles can be readily controlled with high homogeneity and on a large scale, making them ideal for plasmonic applications.…”

Section: Introductionmentioning

confidence: 99%

Silver nanowires for highly reproducible cantilever based AFM-TERS microscopy: towards a universal TERS probe

et al. 2018

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Tip-enhanced Raman scattering (TERS) microscopy is a unique analytical tool to provide complementary chemical and topographic information of surfaces with nanometric resolution. However, difficulties in reliably producing the necessary metallized scanning probe tips has limited its widespread utilisation, particularly in the case of cantilever-based atomic force microscopy. Attempts to alleviate tip related issues using colloidal or bottom-up engineered tips have so far not reported consistent probes for both Raman and topographic imaging. Here we demonstrate the reproducible fabrication of cantilever-based high-performance TERS probes for both topographic and Raman measurements, based on an approach that utilises noble metal nanowires as the active TERS probe. The tips show 10 times higher TERS contrasts than the most typically used electrochemically-etched tips, and show a reproducibility for TERS greater than 90%, far greater than found with standard methods. We show that TERS can be performed in tapping as well as contact AFM mode, with optical resolutions around or below 15 nm, and with a maximum resolution achieved in tapping-mode of 6 nm. Our work illustrates that superior TERS probes can be produced in a fast and cost-effective manner using simple wet-chemistry methods, leading to reliable and reproducible high-resolution and high-sensitivity TERS, and thus renders the technique applicable for a broad community.

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Colloidal Nanoantennas for Hyperspectral Chemical Mapping

Cited by 17 publications

References 42 publications

Enhanced generation and anisotropic Coulomb scattering of hot electrons in an ultra-broadband plasmonic nanopatch metasurface

Enhanced generation and anisotropic Coulomb scattering of hot electrons in an ultra-broadband plasmonic nanopatch metasurface

Tip‐Enhanced Raman Spectroscopy: A Tool for Nanoscale Chemical and Structural Characterization of Biomolecules

Silver nanowires for highly reproducible cantilever based AFM-TERS microscopy: towards a universal TERS probe

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