1
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Li Z, Rigor J, Ehtesabi S, Gojare S, Kupfer S, Gräfe S, Large N, Kurouski D. Role of Plasmonic Antenna in Hot Carrier-Driven Reactions on Bimetallic Nanostructures. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:22635-22645. [PMID: 38357685 PMCID: PMC10863061 DOI: 10.1021/acs.jpcc.3c06520] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 02/16/2024]
Abstract
Noble metal nanostructures can efficiently harvest electromagnetic radiation, which, in turn, is used to generate localized surface plasmon resonances. Surface plasmons decay, producing hot carriers, that is, short-lived species that can trigger chemical reactions on metallic surfaces. However, noble metal nanostructures catalyze only a very small number of chemical reactions. This limitation can be overcome by coupling such nanostructures with catalytic-active metals. Although the role of such catalytically active metals in plasmon-driven catalysis is well-understood, the mechanistics of a noble metal antenna in such chemistry remains unclear. In this study, we utilize tip-enhanced Raman spectroscopy, an innovative nanoscale imaging technique, to investigate the rates and yields of plasmon-driven reactions on mono- and bimetallic gold- and silver-based nanostructures. We found that silver nanoplates (AgNPs) demonstrate a significantly higher yield of 4-nitrobenzenehtiol to p,p'-dimercaptoazobisbenzene (DMAB) reduction than gold nanoplates (AuNPs). We also observed substantially greater yields of DMAB on silver-platinum and silver-palladium nanoplates (Ag@PtNPs and Ag@PdNPs) compared to their gold analogues, Au@PtNPs and Au@PdNPs. Furthermore, Ag@PtNPs exhibited enhanced reactivity in 4-mercatophenylmethanol to 4-mercaptobenzoic acid oxidation compared to Au@PtNPs. These results showed that silver-based bimetallic nanostructures feature much greater reactivity compared to their gold-based analogues.
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Affiliation(s)
- Zhandong Li
- Department
of Biochemistry and Biophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Joel Rigor
- Department
of Physics and Astronomy, The University
of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Sadaf Ehtesabi
- Institute
of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Siddhi Gojare
- Institute
of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Stephan Kupfer
- Institute
of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Stefanie Gräfe
- Institute
of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Nicolas Large
- Department
of Physics and Astronomy, The University
of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Dmitry Kurouski
- Department
of Biochemistry and Biophysics, Texas A&M
University, College
Station, Texas 77843, United States
- The
Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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2
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El-Khoury PZ. Tip-Enhanced Raman Chemical and Chemical Reaction Imaging in H 2O with Sub-3-nm Spatial Resolution. J Am Chem Soc 2023; 145:6639-6642. [PMID: 36919918 DOI: 10.1021/jacs.3c01626] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Reproducible chemical and chemical reaction nanoimaging at solid-liquid interfaces remains challenging, particularly when resolutions on the order of a few nanometers are sought. In this work, we demonstrate the latter through liquid-tip-enhanced Raman (TER) measurements that target gold nanoplates functionalized with 4-mercaptobenzonitrile (MBN). In addition to chemical imaging and local optical field nanovisualization with high spatial resolution, we observe the signatures of 4-mercaptobenzoic acid, which forms as a result of plasmon-induced hydrolysis of MBN. Evidently, the solvent leads to distinct plasmon-induced/enhanced chemical reaction pathways that have not been documented. This work shows that such reactions that take place at solid-liquid interfaces can be tracked with a record sub-3-nm spatial resolution via TER spectral nanoimaging in liquids.
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Affiliation(s)
- Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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3
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Abstract
Solvated electrons are powerful reducing agents capable of driving some of the most energetically expensive reduction reactions. Their generation under mild and sustainable conditions remains challenging though. Using near-ultraviolet irradiation under low-intensity one-photon conditions coupled with electrochemical and optical detection, we show that the yield of solvated electrons in water is increased more than 10 times for nanoparticle-decorated electrodes compared to smooth silver electrodes. Based on the simulations of electric fields and hot carrier distributions, we determine that hot electrons generated by plasmons are injected into water to form solvated electrons. Both yield enhancement and hot carrier production spectrally follow the plasmonic near-field. The ability to enhance solvated electron yields in a controlled manner by tailoring nanoparticle plasmons opens up a promising strategy for exploiting solvated electrons in chemical reactions.
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4
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Mantilla ABC, Wang CF, Gu Y, Schultz ZD, El-Khoury PZ. Multipolar Raman Scattering vs Interfacial Nanochemistry: Case of 4-Mercaptopyridine on Gold. J Am Chem Soc 2022; 144:20561-20565. [PMID: 36343210 PMCID: PMC10193591 DOI: 10.1021/jacs.2c10132] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Caution needs to be exercised in associating changes in plasmon-enhanced Raman spectra with chemical transformations. This is demonstrated through a detailed analysis of tip-enhanced Raman (TER) scattering from 4-mercaptopyridine (MPY) on gold. The substrate used consists of gold nanoplates atop a gold surface featuring heterogeneous grooves, all coated with a monolayer of MPY. The brightest spectra across the substrate exhibit features that can only be recovered by considering the generalized polarizability of oriented MPY molecules. The complex TER spectra we observe do not mark interfacial chemistry but rather multipolar TER scattering driven by local field gradients.
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Affiliation(s)
- Alexander B. C. Mantilla
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, USA
| | - Chih-Feng Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA
| | - Yi Gu
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, USA
| | - Zachary D. Schultz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Patrick Z. El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA
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5
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Su HS, Chang X, Xu B. Surface-enhanced vibrational spectroscopies in electrocatalysis: Fundamentals, challenges, and perspectives. CHINESE JOURNAL OF CATALYSIS 2022. [DOI: 10.1016/s1872-2067(22)64157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Bryche JF, Vega M, Tempez A, Brulé T, Carlier T, Moreau J, Chaigneau M, Charette PG, Canva M. Spatially-Localized Functionalization on Nanostructured Surfaces for Enhanced Plasmonic Sensing Efficacy. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3586. [PMID: 36296775 PMCID: PMC9609756 DOI: 10.3390/nano12203586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
This work demonstrates the enhancement in plasmonic sensing efficacy resulting from spatially-localized functionalization on nanostructured surfaces, whereby probe molecules are concentrated in areas of high field concentration. Comparison between SERS measurements on nanostructured surfaces (arrays of nanodisks 110 and 220 nm in diameter) with homogeneous and spatially-localized functionalization with thiophenol demonstrates that the Raman signal originates mainly from areas with high field concentration. TERS measurements with 10 nm spatial resolution confirm the field distribution profiles predicted by the numerical modeling. Though this enhancement in plasmonic sensing efficacy is demonstrated with SERS, results apply equally well to any type of optical/plasmonic sensing on functionalized surfaces with nanostructuring.
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Affiliation(s)
- Jean-François Bryche
- Laboratoire Nanotechnologies Nanosystèmes (LN2-IRL 3463)-CNRS, Université de Sherbrooke, 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
- Institut Interdisciplinaire d’Innovation Technologique (3IT), 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
| | - Marlo Vega
- Laboratoire Nanotechnologies Nanosystèmes (LN2-IRL 3463)-CNRS, Université de Sherbrooke, 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
- Institut Interdisciplinaire d’Innovation Technologique (3IT), 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
- Laboratoire Charles Fabry—Institut d’Optique Graduate School, Université Paris-Saclay, CNRS, 91120 Palaiseau, France
| | | | | | | | - Julien Moreau
- Laboratoire Charles Fabry—Institut d’Optique Graduate School, Université Paris-Saclay, CNRS, 91120 Palaiseau, France
| | | | - Paul G. Charette
- Laboratoire Nanotechnologies Nanosystèmes (LN2-IRL 3463)-CNRS, Université de Sherbrooke, 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
- Institut Interdisciplinaire d’Innovation Technologique (3IT), 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
| | - Michael Canva
- Laboratoire Nanotechnologies Nanosystèmes (LN2-IRL 3463)-CNRS, Université de Sherbrooke, 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
- Institut Interdisciplinaire d’Innovation Technologique (3IT), 3000 Boulevard de l’Université, Sherbrooke, QC J1K OA5, Canada
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7
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Shabani S, Darlington TP, Gordon C, Wu W, Yanev E, Hone J, Zhu X, Dreyer CE, Schuck PJ, Pasupathy AN. Ultralocalized Optoelectronic Properties of Nanobubbles in 2D Semiconductors. NANO LETTERS 2022; 22:7401-7407. [PMID: 36122409 DOI: 10.1021/acs.nanolett.2c02265] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The optical properties of transition-metal dichalcogenides have previously been modified at the nanoscale by using mechanical and electrical nanostructuring. However, a clear experimental picture relating the local electronic structure with emission properties in such structures has so far been lacking. Here, we use a combination of scanning tunneling microscopy (STM) and near-field photoluminescence (nano-PL) to probe the electronic and optical properties of single nanobubbles in bilayer heterostructures of WSe2 on MoSe2. We show from tunneling spectroscopy that there are electronic states deeply localized in the gap at the edge of such bubbles, which are independent of the presence of chemical defects in the layers. We also show a significant change in the local band gap on the bubble, with a continuous evolution to the edge of the bubble over a length scale of ∼20 nm. Nano-PL measurements observe a continuous redshift of the interlayer exciton on entering the bubble, in agreement with the band-to-band transitions measured by STM. We use self-consistent Schrödinger-Poisson simulations to capture the essence of the experimental results and find that strong doping in the bubble region is a key ingredient to achieving the observed localized states, together with mechanical strain.
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Affiliation(s)
- Sara Shabani
- Department of Physics, Columbia University, New York 10027, New York, United States
| | - Thomas P Darlington
- Department of Mechanical Engineering, Columbia University, New York 10027, New York, United States
| | - Colin Gordon
- Department of Physics and Astronomy, Stony Brook University, Stony Brook 11790, New York, United States
| | - Wenjing Wu
- Department of Chemistry, Columbia University, New York 10027, New York, United States
| | - Emanuil Yanev
- Department of Mechanical Engineering, Columbia University, New York 10027, New York, United States
| | - James Hone
- Department of Mechanical Engineering, Columbia University, New York 10027, New York, United States
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York 10027, New York, United States
| | - Cyrus E Dreyer
- Center for Computational Quantum Physics, Flatiron Institute, New York 10010, New York, United States
| | - P James Schuck
- Department of Mechanical Engineering, Columbia University, New York 10027, New York, United States
| | - Abhay N Pasupathy
- Department of Physics, Columbia University, New York 10027, New York, United States
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8
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Li Z, Kurouski D. Can Light Alter the Yield of Plasmon-Driven Reactions on Gold and Gold-Palladium Nanoplates? NANO LETTERS 2022; 22:7484-7491. [PMID: 36122388 DOI: 10.1021/acs.nanolett.2c02428] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Noble-metal nanostructures, as well as their bimetallic analogues, catalyze a broad spectrum of plasmon-driven reactions. Catalytic properties of such nanostructures arise from light-generated surface plasmon resonances that decay forming transient hot electrons and holes. Hot carriers with "slower" dissipation rates accumulate on nanostructures generating an electrostatic potential. In this study, we examine whether light intensity can alter the electrostatic potential of mono- and bimetallic nanostructures changing yields of plasmon-driven reactions. Using tip-enhanced Raman spectroscopy (TERS), we quantified the yield of plasmon-driven transformations of 4-nitrobenzenethiol (4-NBT) and 3-mercaptobenzoic acid (3-MBA) on gold and gold-palladium nanoplates (AuNPs and Au@PdNPs, respectively). We found that on AuNPs 3-MBA decarboxylated forming thiophenol (TP), whereas 4-NBT was reduced to DMAB. The yield of both TP and DMAB gradually increased with increasing light intensity. On Au@PdNPs, 3-MBA could be reduced to 3-mercaptophenylmethanol (3-MPM), the yield of which was also directly dependent on the light intensity.
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Affiliation(s)
- Zhandong Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Dmitry Kurouski
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
- The Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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9
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O'Callahan BT, El-Khoury PZ. A Closer Look at Tip-Enhanced Raman Chemical Reaction Nanoimages. J Phys Chem Lett 2022; 13:3886-3889. [PMID: 35470671 DOI: 10.1021/acs.jpclett.2c00574] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Tip-enhanced Raman spectroscopy (TERS) is a powerful technique that enables ultrahigh spatial resolution and ultrasensitive chemical imaging. This technique's ability to track plasmon-induced/enhanced chemical reactions in real space has gained increasing popularity in recent years. In this study, we expose inherent difficulties associated with assigning TERS signatures that accompany chemical transformations. Namely, distinct selection rules as well as the possibility of multiple physical processes/chemical reaction pathways complicate spectral assignments and necessitate caution in assigning the experimental observables. We illustrate the latter using 4,4'-dimercaptostilbene-functionalized plasmonic silver nanocubes, wherein we identify the TERS signatures of product formation, molecular charging, multipolar Raman scattering, and preferred molecular orientations that all lead to distinct and assignable spectral patterns.
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Affiliation(s)
- Brian T O'Callahan
- Earth and Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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10
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Proniewicz E, Olszewski TK. SERS/TERS Characterization of New Potential Therapeutics: The Influence of Positional Isomerism, Interface Type, Oxidation State of Copper, and Incubation Time on Adsorption on the Surface of Copper(I) and (II) Oxide Nanoparticles. J Med Chem 2022; 65:4387-4400. [PMID: 35230122 PMCID: PMC8919263 DOI: 10.1021/acs.jmedchem.2c00031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
The aim of this study
was to investigate how the oxidation state
of copper (Cu(I) vs Cu(II)), the nature of the interface (solid/aqueous
vs solid/air), positional isomerism, and incubation time affect the
functionalization of the surface of copper oxide nanostructures by
[(butylamino)(pyridine)methyl]phenylphosphinic acid (PyPA). For this
purpose, 2-, 3-, and 4-isomers of PyPA and the nanostructures were
synthesized. The nanostructure were characterized by UV-visible spectroscopy
(UV–vis), scanning electron microscopy (SEM), Raman spectroscopy
(RS), and X-ray diffraction (XRD) analysis, which proved the formation
of spherical Cu2O nanoparticles (Cu2ONPs; 1500–600
nm) and leaf-like CuO nanostructures (CuONSs; 80–180/400–700
nm, width/length). PyPA isomers were deposited on the surface of NSs,
and adsorption was investigated by surface-enhanced Raman scattering
(SERS) and tip-enhanced Raman scattering (TERS). The changes of adsorption
on the surface of copper oxide NSs caused by the above-mentioned factors
were described and the enhancement factor on this substrate was calculated.
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Affiliation(s)
- Edyta Proniewicz
- Faculty of Foundry Engineering, AGH University of Science and Technology, ul. Reymonta 23, 30-059 Kraków, Poland.,Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-137, Japan
| | - Tomasz K Olszewski
- Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
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11
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Abstract
Historically, molecular spectroscopists have focused their attention to the right-hand side of the Schrödinger equation. Our major goal had and still has to do with determining a (bio)molecular system's Hamiltonian operator. From a theoretical spectroscopist's perspective, this entails varying the parameters of a model Hamiltonian until the predicted observables agree with their experimental analogues. In this context, less emphasis has been put on the left-hand side of the equation, where the interplay between a system and its immediate local environment is described. The latter is particularly meaningful and informative in modern applications of optical microscopy and spectroscopy that take advantage of surface plasmons to enhance molecular scattering cross-sections and to increase the attainable spatial resolution that is classically limited by diffraction. Indeed, the manipulation of light near the apex of a metallic nanotip has enabled single molecule detection, identification, and imaging. The distinct advantages of the so-called tip-enhanced optical nanospectroscopy/nanoimaging approaches are self-evident: ultrahigh spatial resolution (nanometer or better) and ultimate sensitivity (down to yoctomolar) are both attainable, all while retaining the ability to chemically fingerprint one molecule at a time (e.g., through Raman scattering). An equally interesting aspect of the same approach stems from using the properties of a single molecule to characterize the local environment in which it resides. This concept of single molecule spectroscopy on the left-hand side of the Schrödinger equation is certainly not novel and has been discussed in pioneering single molecule studies that ultimately led to a Nobel prize in chemistry. That said, local environment mapping through ultrasensitive optical spectroscopy acquires a unique flavor when executed using tip-enhanced Raman scattering (TERS). This is the subject of this Account.In a series of recent reports, our group utilized TERS to characterize different properties of nanolocalized and enhanced optical fields. The platforms that were used to this end consist of chemically functionalized plasmonic nanostructures and nanoparticles imaged using visible-light-irradiated gold- or silver-coated probes of an atomic force microscope. Through a detailed analysis of the recorded spectral nanoimages, we found that molecular Raman spectra may be used to track the magnitudes, resonances, spatiotemporal gradients, and even vector components of optical fields with nanometer spatial resolution under ambient conditions. On the other side of the equation, understanding how spatially varying optical fields modulate molecular nano-Raman spectra is of utmost importance to emerging areas of nanophotonics. For instance, tracking plasmon-enhanced chemical transformations via TERS necessitates a deeper fundamental understanding of the optical signatures of molecular reorientation and multipolar Raman scattering, both of which may be driven by local optical field gradients that are operative in TERS. We illustrate these concepts and introduce the readers to the generally less appreciated and equally exciting world of TERS on the left-hand side of the Schrödinger equation.
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Affiliation(s)
- Patrick Z. El-Khoury
- Chemical Physics and Analysis Group, Physical Sciences Division, Pacific Northwest National Laboratory; Richland, Washington 99352, United States
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12
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de Albuquerque CDL, Zoltowski CM, Scarpitti BT, Shoup DN, Schultz ZD. Spectrally Resolved Surface-Enhanced Raman Scattering Imaging Reveals Plasmon-Mediated Chemical Transformations. ACS NANOSCIENCE AU 2021; 1:38-46. [PMID: 34966910 PMCID: PMC8700175 DOI: 10.1021/acsnanoscienceau.1c00031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 02/08/2023]
Abstract
![]()
Challenges investigating
molecules on plasmonic nanostructures
have limited understanding of these interactions. However, the chemically
specific information in the surface-enhanced Raman scattering (SERS)
spectrum can identify perturbations in the adsorbed molecules to provide
insight relevant to applications in sensing, catalysis, and energy
conversion. Here, we demonstrate spectrally resolved SERS imaging,
to simultaneously image and collect the SERS spectra from molecules
adsorbed on individual nanoparticles. We observe intensity and frequency
fluctuations in the SERS signal on the time scale of tens of milliseconds
from n-mercaptobenzoic acid (MBA) adsorbed to gold
nanoparticles. The SERS signal fluctuations correlate with density
functional theory calculations of radicals generated by the interaction
between MBA and plasmon-generated hot electrons. Applying localization
microscopy to the data provides a super-resolution spectrally resolved
map that indicates the plasmonic-induced molecular charging occurs
on the extremities of the nanoparticles, where the localized electromagnetic
field is reported to be most intense.
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Affiliation(s)
| | - Chelsea M Zoltowski
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Brian T Scarpitti
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Deben N Shoup
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zachary D Schultz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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13
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Wang CF, El-Khoury PZ. Multimodal Tip-Enhanced Nonlinear Optical Nanoimaging of Plasmonic Silver Nanocubes. J Phys Chem Lett 2021; 12:10761-10765. [PMID: 34714090 DOI: 10.1021/acs.jpclett.1c03196] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Optical field localization at plasmonic tip-sample nanojunctions has enabled high-spatial-resolution chemical analysis through tip-enhanced linear optical spectroscopies, including Raman scattering and photoluminescence. Here, we illustrate that nonlinear optical processes, including parametric four-wave mixing (4WM), second-harmonic/sum-frequency generation (SHG and SFG), and two-photon photoluminescence (TPPL), can be enhanced at plasmonic junctions and spatiospectrally resolved simultaneously with few-nm spatial resolution under ambient conditions. Through a detailed analysis of our spectral nanoimages, we find that the efficiencies of the local nonlinear signals are determined by sharp tip-sample junction resonances that vary over the few-nanometer length scale. Namely, plasmon resonances centered at or around the different nonlinear signals are tracked through TPPL, and they are found to selectively enhance nonlinear signals with closely matched optical resonances.
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Affiliation(s)
- Chih-Feng Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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14
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Wang CF, O'Callahan BT, Krayev A, El-Khoury PZ. Nanoindentation-enhanced tip-enhanced Raman spectroscopy. J Chem Phys 2021; 154:241101. [PMID: 34241355 DOI: 10.1063/5.0056541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We combine nanoindentation, herein achieved using atomic force microscopy-based pulsed-force lithography, with tip-enhanced Raman spectroscopy (TERS) and imaging. Our approach entails indentation and multimodal characterization of otherwise flat Au substrates, followed by chemical functionalization and TERS spectral imaging of the indented nanostructures. We find that the resulting structures, which vary in shape and size depending on the tip used to produce them, may sustain nano-confined and significantly enhanced local fields. We take advantage of the latter and illustrate TERS-based ultrasensitive detection/chemical fingerprinting as well as chemical reaction imaging-all using a single platform for nano-lithography, topographic imaging, hyperspectral dark field optical microscopy, and TERS.
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Affiliation(s)
- Chih-Feng Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Brian T O'Callahan
- Earth and Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Andrey Krayev
- Horiba Instruments, Inc., 359 Bel Marin Keys Blvd., Suite 18, Novato, California 94949, USA
| | - Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
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15
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Gabel M, O'Callahan BT, Groome C, Wang CF, Ragan R, Gu Y, El-Khoury PZ. Mapping Molecular Adsorption Configurations with <5 nm Spatial Resolution through Ambient Tip-Enhanced Raman Imaging. J Phys Chem Lett 2021; 12:3586-3590. [PMID: 33819047 DOI: 10.1021/acs.jpclett.1c00661] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We interrogate para-mercaptobenzoic acid (MBA) molecules chemisorbed onto plasmonic silver nanocubes through tip-enhanced Raman (TER) spectral nanoimaging. Through a detailed examination of the spectra, aided by correlation analysis and density functional theory calculations, we find that MBA chemisorbs onto the plasmonic particles with at least two distinct configurations: S- and CO2-bound. High spatial resolution TER mapping allows us to distinguish between the distinct adsorption geometries with a pixel-limited (<5 nm) spatial resolution under ambient laboratory conditions.
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Affiliation(s)
- Matthew Gabel
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
| | - Brian T O'Callahan
- Earth and Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Chloe Groome
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, California 92697-2575, United States
| | - Chih-Feng Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Regina Ragan
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, California 92697-2575, United States
| | - Yi Gu
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
| | - Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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