Review
Chemistry, Multidisciplinary
Sebastien Bonhommeau, Gary S. Cooney, Yuhan Huang
Summary: Nanoscale chemical and structural characterization of single biomolecules and assemblies using Tip-enhanced Raman scattering (TERS) spectroscopy is crucial for understanding biological processes and diseases at the molecular level. TERS has been used to study nucleic acids, proteins, lipids, cells, viruses, and amyloid fibrils with unprecedented spatial resolution. Advances in TERS have allowed for DNA and RNA sequencing, identification of protein-lipid interactions, and characterization of lipid membrane organization, with potential applications in biology, biomedicine, and clinical settings.
CHEMICAL SOCIETY REVIEWS
(2022)
Article
Chemistry, Physical
Jiaqi Shao, Fei Chen, Weitao Su, Naresh Kumar, Yijie Zeng, Ling Wu, Hong-Wei Lu
Summary: In this study, high-resolution tip-enhanced photoluminescence microscopy was applied to investigate exciton funneling at nanoscale wrinkles in t2L MoS2 samples. The results provided novel insights into the inhomogeneities of excitonic behaviors at nanoscale and could aid in the rational design of twistronic devices based on 2D materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Dusan Mrdenovic, Wenjie Ge, Naresh Kumar, Renato Zenobi
Summary: Here, the researchers used tip-enhanced Raman spectroscopy (TERS) to visualize the molecular distribution in pancreatic cancer cell membranes without labeling. The study revealed various domains and mixed regions on the nanoscale of the cell membrane.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Gary Sean Cooney, David Talaga, Vicky Ury-Thiery, Yann Fichou, Yuhan Huang, Sophie Lecomte, Sebastien Bonhommeau
Summary: In this study, TERS was used to visualize the spatial distribution of adenine, protein secondary structure, and amino acids in single polyadenosine-induced tau fibrils. The findings provide insights into the incorporation of the polyadenosine cofactor in the fibril structure and its interaction with amino acids. TERS proves to be a powerful technique for studying cofactors in individual tau fibrils and their mode of interaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Yashashwa Pandey, Naresh Kumar, Guillaume Goubert, Renato Zenobi
Summary: Raman spectroscopy technology exhibits high resolution and sensitivity in investigating the molecular organization of supported DPPC monolayers, demonstrating the heterogeneity of lipid membranes at the nanoscale.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Stanislav Rizevsky, Dmitry Kurouski
Summary: The translation article introduces the wide application of tip-enhanced Raman spectroscopy (TERS), an emerging analytical technique, in the study of plasmon-driven catalysis and photocatalytic properties over the past decade. TERS provides single-molecule sensitivity and subnanometer spatial resolution, enabling in situ catalysis, visualization of chemical reactions, and offers prospects for the future of TERS in photochemistry and material sciences.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Matthias Filez, Peter Walke, Hai Le-The, Shuichi Toyouchi, Wannes Peeters, Patrick Tomkins, Jan C. T. Eijkel, Steven De Feyter, Christophe Detavernier, Dirk E. De Vos, Hiroshi Uji-I, Maarten B. J. Roeffaers
Summary: This study demonstrates the first-time application of tip-enhanced Raman spectroscopy (TERS) as a nanoscale chemical probe to localize and identify coke deposits. The results reveal the chemical diversity and distribution of coke at the nanoscale, providing novel guidelines for selectively removing coke and improving catalyst stability.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Denis E. Tranca, Stefan G. Stanciu, Radu Hristu, Adrian M. Ionescu, George A. Stanciu
Summary: We present a viable method to modify the refractive index of PMMA by focusing a femtosecond pulsed near-infrared laser beam on the apex of a metalized nanosized tip. The refractive index can be changed over a circular area with a diameter <200 nm under 790 nm illumination, representing a four-fold increase in resolution compared to the current state-of-the-art methods. This method can have important applications in the fabrication of photonic crystal lattices and surface waveguides.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Applied
D. Seidlitz, E. Poliani, M. Ries, A. Hoffmann, M. R. Wagner
Summary: The compositional homogeneity of InGaN thin films with a high In content grown by migration-enhanced plasma-assisted metal-organic chemical vapor deposition was investigated using micro-Raman spectroscopy and tip-enhanced Raman spectroscopy. The study revealed intrinsic phase separations and nanoscale compositional inhomogeneities within the films. Tip-enhanced Raman spectroscopy was able to quantify the In content in different compositional regions and identify InN nanoclusters near the film surface, providing a more detailed analysis compared to other techniques like scattering-type scanning near-field infrared nanoscopy.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Cla Duri Tschannen, Martin Frimmer, Thiago L. Vasconcelos, Lei Shi, Thomas Pichler, Lukas Novotny
Summary: This paper demonstrates the use of tip-enhanced Raman scattering (TERS) to enhance the Raman response of a single carbyne chain. The study observes a significant increase in scattering and discusses the role of coherent Stokes-anti-Stokes scattering mediated by an excited phonon. The resonance effects and laser-induced heating are also discussed, along with potential opportunities.
Article
Chemistry, Multidisciplinary
Ben Yang, Gong Chen, Atif Ghafoor, Yu-Fan Zhang, Xian-Biao Zhang, Hang Li, Xiao-Ru Dong, Rui-Pu Wang, Yang Zhang, Yao Zhang, Zhen-Chao Dong
Summary: We investigated the chemical effects on Raman signals in surface enhanced Raman spectroscopy (SERS) through tip-enhanced Raman spectroscopy (TERS) of a single planar ZnPc molecule with controlled contact environments. TERS signals were enhanced when a tip-molecule point contact was made, due to the generation of a ground-state charge-transfer induced vertical Raman polarizability and the strong vertical plasmonic field in the nanocavity. However, TERS signals were quenched when ZnPc was chemisorbed flatly on substrates, attributed to the Raman polarizability screening effect induced by interfacial dynamic charge transfer.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Chih-Feng Wang, Mikhail Zamkov, Patrick Z. El-Khoury
Summary: This study achieves record spatial resolution in ambient tip-enhanced photoluminescence (TEPL) from CdSe/ZnS semiconductor quantum dots by taking advantage of surface roughness at the apex of a sputtered plasmonic gold probe. The reproducibility of observations is demonstrated using different plasmonic probes and samples. The high spatial resolution in TEPL is attributed to field enhancement at the metal tip-fluorophore interface.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Multidisciplinary
Shuyi Liu, Martin Wolf, Takashi Kumagai
Summary: We investigated the nanoscale heating mechanism of an ultrathin ZnO film using low-temperature tip-enhanced Raman spectroscopy. The results revealed that the local heating is mainly caused by inelastic electron tunneling and optical excitation processes, which are promoted by localized surface plasmon excitation. Mapping the 2-ML ZnO allowed visualization of the correlation between heating efficiency and local density of states, providing insight into the local electron-phonon coupling strength.
PHYSICAL REVIEW LETTERS
(2022)
Review
Chemistry, Multidisciplinary
Dusan Mrdenovic, Zhen-Feng Cai, Yashashwa Pandey, Giovanni Luca Bartolomeo, Renato Zenobi, Naresh Kumar
Summary: Two-dimensional (2D) molecular materials have attracted great attention due to their unique properties and potential applications. However, sensitive analytical tools are needed to understand the structure-property relationship of these materials at the nanoscale. Tip-enhanced Raman spectroscopy (TERS) has emerged as a powerful technique for nanoscale chemical analysis by combining scanning probe microscopy and surface-enhanced Raman spectroscopy. In this review, the application of TERS for nanoscale chemical analysis of 2D molecular materials is discussed, and the progress in structural and chemical characterization is demonstrated with examples.
Review
Chemistry, Multidisciplinary
Ilya A. Milekhin, Alexander G. Milekhin, Dietrich R. T. Zahn
Summary: This study presents the optical response of spherical CdSe nanocrystals using SERS and TERS techniques, achieving significant enhancement of optical phonons by selecting appropriate plasmonic substrates. Combining Raman scattering with atomic force microscopy offers nanoscale spatial resolution for investigating phonon properties. Gap-mode TERS further enhances Raman scattering of CdSe NCs' optical phonon modes with nanometer spatial resolution, providing new pathways for optical characterization and phonon spectrum details at the nanometer scale of single semiconductor nanostructures.
Article
Physics, Applied
Kevin T. Crampton, Alan G. Joly, Patrick Z. El-Khoury
Summary: The role of surface plasmon polaritons (SPPs) in nanohole array optical extinction spectra is investigated, and a selective SPP spectroscopy method is proposed. The color and bandwidth of narrowband SPPs in the counter-propagating direction can be controlled by tuning the array pitch.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Chih-Feng Wang, Brian T. O'Callahan, Bruce W. Arey, Dmitry Kurouski, Patrick Z. El-Khoury
Summary: In this study, high-resolution TER spectral images of functionalized plasmonic metal nanoparticles were recorded using an imperfect probe. The effects of the probe on the images were discussed, and the orientation of BTP molecules on the surface was determined by comparing the recorded spectra with and without the plasmonic tip.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Brian T. O'Callahan, Patrick Z. El-Khoury
Summary: Tip-enhanced Raman spectroscopy is a powerful technique for high-resolution chemical imaging. It can track plasmon-induced/enhanced chemical reactions and provide accurate spectral assignments.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Chih-Feng Wang, Patrick Z. El-Khoury
Summary: This article highlights recent advances in linear and nonlinear spectral nanoimaging, emphasizing the importance of high spatial resolution measurements conducted under ambient laboratory conditions. It describes the motivation behind these developments and their applications in various fields.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Alvaro Rodriguez, Andrey Krayev, Matej Velicky, Otakar Frank, Patrick Z. El-Khoury
Summary: The interaction between excitons and phonons plays a crucial role in the optical and electronic properties of transition metal dichalcogenides (TMDs). This article introduces a new method called ultralow-frequency tip-enhanced Raman spectroscopy, which allows direct probing of ultralow-frequency and interlayer phonons at the nanoscale. The method was applied to analyze phonons in nanobubbles within TMD heterobilayers, providing insights into the interplay between excitons and interlayer/intralayer phonons.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Chih-Feng Wang, Alexander B. C. Mantilla, Yi Gu, Patrick Z. El-Khoury
Summary: Nonlinear nano-optical measurements combining ultrafast spectroscopy with scanning probe microscopy are performed to achieve high spatial resolution tracking of two-photon photoluminescence from CdSe/ZnS quantum dot aggregates under ambient conditions. The use of a plasmonic probe instead of a gap mode enables nonlinear photoluminescence-based spectral nanoimaging of realistic/heterogeneous (bio)molecular and (bio)material systems.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Laura M. Obloy, Patrick Z. El-Khoury, Alexander N. Tarnovsky
Summary: The excited-state dynamics of trans-4,4'-azopyridine in ethanol were investigated using femtosecond transient absorption. Vibrational coherence was observed in both S1 n pi* and S2 pi pi* electronic states. The relaxation pathway showed nonrotational behavior, with population being trapped in planar and shallow minima before decaying into the ground state. Nonrotational relaxation and the formation of hot ground-state species were observed upon excitation of the S2 state. The cis-isomer quantum yield increased with pi pi* excitation, in contrast to trans-azobenzene.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Alexander B. C. Mantilla, Chih-Feng Wang, Yi Gu, Zachary D. Schultz, Patrick Z. El-Khoury
Summary: This study warns about the caution needed when associating changes in plasmon-enhanced Raman spectra with chemical transformations. The research demonstrates this by analyzing in detail the tip-enhanced Raman (TER) scattering from 4-mercaptopyridine (MPY) on gold. The brightest spectra on the substrate can only be recovered by considering the generalized polarizability of oriented MPY molecules. The complex TER spectra observed do not indicate interfacial chemistry but instead reveal multipolar TER scattering driven by local field gradients.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Alexander B. C. Mantilla, Bethany E. Matthews, Yi Gu, Patrick Z. El-Khoury
Summary: Selective interfacial transformations, particularly oxidation reactions, can be achieved using monometallic silver nanoparticles instead of bimetallic nanostructures. The tip-enhanced Raman spectroscopy images of ATP-functionalized Au and Ag nanoparticles show that while dimerization dominates on Au leading to 4,4'-dimercaptoazobenzene, oxidation exclusively leads to 4-nitrothiophenol on Ag nanoparticles. The distinct reaction pathways on Ag vs Au nanostructures are explored.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Patrick Z. El-Khoury
Summary: Reproducible chemical and chemical reaction nanoimaging at solid-liquid interfaces with resolutions on the order of a few nanometers is demonstrated using liquid-tip-enhanced Raman (TER) measurements. The TER spectral nanoimaging in liquids allows for chemical imaging, local optical field nanovisualization, and observation of distinct plasmon-induced/enhanced chemical reaction pathways at solid-liquid interfaces. The study highlights the significance of tracking such reactions with sub-3-nm spatial resolution.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Chih-Feng Wang, Alexander B. C. Mantilla, Andrey Krayev, Yi Gu, Patrick Z. El-Khoury
Summary: In this study, we propose a method for nanoscale local optical field imaging using tip-enhanced Raman scattering (TERS). We demonstrate that ultralow frequency Raman scattering can be used for non-invasive local field imaging with high spatial resolution and the ability to distinguish between different materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Chih-Feng Wang, Andrey V. Krayev, Patrick Z. El-Khoury
Summary: This study addresses the challenge of quantitatively describing local optical field variations in ultrahigh spatial resolution measurements through extinction-based spectral nanoimaging experiments, achieving spatial resolution of <1 nm.
Article
Chemistry, Multidisciplinary
Oliva M. M. Primera-Pedrozo, Shuai Tan, Difan Zhang, Brian T. T. O'Callahan, Wenjin Cao, Eric T. T. Baxter, Xue-Bin Wang, Patrick Z. Z. El-Khoury, Venkateshkumar Prabhakaran, Vassiliki-Alexandra Glezakou, Grant E. E. Johnson
Summary: This study synthesized Keggin POMs with both tungsten and vanadium atoms and used ion soft landing to deliver these POMs to different self-assembled monolayer surfaces on gold. The interactions between POMs and supports, as well as POMs and neighboring POMs, were characterized using various spectroscopic techniques. The results showed that surface functional groups and nanoscale heterogeneity can modulate the observed spectroscopic signatures, and POM-POM interactions also affect the spectral shifts.
Review
Chemistry, Multidisciplinary
Patrick Z. Z. El-Khoury
Summary: This article summarizes the lessons learned from ambient tip-enhanced Raman (TER) mapping of molecules interacting with plasmonic nanostructures. It demonstrates that various physical and chemical phenomena play a role in producing high-resolution TER spectral images. Consequently, selectively tracking interfacial chemical transformations via TERS is more challenging than currently recognized.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Venkateshkumar Prabhakaran, Joelle Romo, Ashish Bhattarai, Kyle George, Zachary M. Norberg, David Kalb, Edoardo Apra, Peter A. Kottke, Andrei G. Fedorov, Patrick Z. El-Khoury, Grant E. Johnson, Julia Laskin
Summary: The exceptional properties of polyoxometalate anions, PW12O403-, including photochromism and redox reactions, have been utilized to develop an integrated photoelectrochemical energy storage cell. By removing strongly coordinating cations, the device's maximum power output has increased by approximately 370%. Furthermore, the photocathode undergoes a noticeable color change upon irradiation, suggesting potential applications in advanced smart windows and photochromic lenses.
CHEMICAL COMMUNICATIONS
(2022)
