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Yikai Xu

Bio: Yikai Xu is an academic researcher from Queen's University Belfast. The author has contributed to research in topics: Nanoparticle & Medicine. The author has an hindex of 8, co-authored 24 publications receiving 989 citations. Previous affiliations of Yikai Xu include East China University of Science and Technology.

Papers
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Journal ArticleDOI
28 Jan 2020-ACS Nano
TL;DR: Prominent authors from all over the world joined efforts to summarize the current state-of-the-art in understanding and using SERS, as well as to propose what can be expected in the near future, in terms of research, applications, and technological development.
Abstract: The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

1,768 citations

Journal ArticleDOI
TL;DR: Nonmetallic particles including TiO2 and SiO2 are allowed to be assembled into dense interfacial layers using the same procedure as is used for metallic particles, opening up a route to a new family of nanostructured functional materials.
Abstract: Two-dimensional metal nanoparticle arrays are normally constructed at liquid–oil interfaces by modifying the surfaces of the constituent nanoparticles so that they self-assemble. Here we present a general and facile new approach for promoting such interfacial assembly without any surface modification. The method use salts that have hydrophobic ions of opposite charge to the nanoparticles, which sit in the oil layer and thus reduce the Coulombic repulsion between the particles in the organic phase, allowing the particles to sit in close proximity to each other at the interface. The advantage of this method is that because it does not require the surface of the particles to be modified it allows nonmetallic particles including TiO2 and SiO2 to be assembled into dense interfacial layers using the same procedure as is used for metallic particles. This opens up a route to a new family of nanostructured functional materials.

79 citations

Journal ArticleDOI
TL;DR: Here, the state-of-the-art progress in the construction of smart multifunctional enhancing substrates are reviewed, holding the key to achieving sustainability and widespread applications of SERS.
Abstract: Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique, which allows quantitative detection of chemical species with molecular specificity and single-molecule sensitivity. These useful properties can be further combined with portable Raman spectrometers which allow SERS to be potentially employed at the point-of-care. As a result, SERS has found a wide range of potential applications in both real-life chemical analysis and fundamental mechanistic studies. Despite these advantages, true applications of SERS have been limited due to its high cost, which arises mainly from the fact that SERS relies on expensive single-use Ag/Au enhancing substrates suitable only for the analysis of pure samples. A viable approach to address this issue is to develop multifunctional SERS substrates, which in addition to providing Raman signal enhancement, is armed with other practical functionalities that simplifies the analysis and/or allows the substrate to be regenerated for repeated use. This review gives an account of the recent progress in the fabrication of multi-functional SERS substrates, namely flexible, separation-enhancement-in-one, calibration-enhancement-in-one and regeneration-enhancement-in-one substrates. Specific focus is placed on summarizing and discussing the most widely used strategies to incorporate each type of functionality and their respective advantages and drawbacks. Finally, we present our perspectives on the future challenges and potential opportunities in the development of smart multifunctional SERS sensors for achieving sustainable and wide-spread application of SERS.

56 citations

Journal ArticleDOI
TL;DR: The addition of Mn in the Fe-based catalyst enhanced the metal-support interactions and the dispersion of metal particles, thus leading to the improved catalytic performance in relation to filamentous carbon growth.

46 citations

Journal ArticleDOI
TL;DR: The opportunity that this approach to SERS provides is illustrated with examples where the surface chemistry is both characterized and controlled in order to create functional nanomaterials.
Abstract: Surface-enhanced Raman spectroscopy (SERS) is now widely used as a rapid and inexpensive tool for chemical/biochemical analysis. The method can give enormous increases in the intensities of the Raman signals of low-concentration molecular targets if they are adsorbed on suitable enhancing substrates, which are typically composed of nanostructured Ag or Au. However, the features of SERS that allow it to be used as a chemical sensor also mean that it can be used as a powerful probe of the surface chemistry of any nanostructured material that can provide SERS enhancement. This is important because it is the surface chemistry that controls how these materials interact with their local environment and, in real applications, this interaction can be more important than more commonly measured properties such as morphology or plasmonic absorption. Here, the opportunity that this approach to SERS provides is illustrated with examples where the surface chemistry is both characterized and controlled in order to create functional nanomaterials.

45 citations


Cited by
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Journal ArticleDOI
28 Jan 2020-ACS Nano
TL;DR: Prominent authors from all over the world joined efforts to summarize the current state-of-the-art in understanding and using SERS, as well as to propose what can be expected in the near future, in terms of research, applications, and technological development.
Abstract: The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

1,768 citations

Journal ArticleDOI
TL;DR: An overview of the most significant aspects of surface-enhanced Raman scattering, and a representative selection of applications in the biomedical field, with direct and indirect protocols is provided.

474 citations

Journal ArticleDOI
TL;DR: An international team of scientists with long‐standing expertise in SERS is presented by presenting considerations on reliable and quantitative SERS to increase the inter‐laboratory comparability of experimental SERS results and further establish SERS as an analytical tool.
Abstract: Experimental results obtained in different laboratories world-wide by researchers using surface-enhanced Raman scattering (SERS) can differ significantly. We, an international team of scientists with long-standing expertise in SERS, address this issue from our perspective by presenting considerations on reliable and quantitative SERS. The central idea of this joint effort is to highlight key parameters and pitfalls that are often encountered in the literature. To that end, we provide here a series of recommendations on: a) the characterization of solid and colloidal SERS substrates by correlative electron and optical microscopy and spectroscopy, b) on the determination of the SERS enhancement factor (EF), including suitable Raman reporter/probe molecules, and finally on c) good analytical practice. We hope that both newcomers and specialists will benefit from these recommendations to increase the inter-laboratory comparability of experimental SERS results and further establish SERS as an analytical tool.

258 citations

Journal ArticleDOI
TL;DR: This review comprehensively summarize the latest advances on state-of-art synthetic strategies, unique properties, and promising applications of multicomponent plasmonic nanoparticles.
Abstract: Plasmonic nanostructures possessing unique and versatile optoelectronic properties have been vastly investigated over the past decade. However, the full potential of plasmonic nanostructure has not yet been fully exploited, particularly with single-component homogeneous structures with monotonic properties, and the addition of new components for making multicomponent nanoparticles may lead to new-yet-unexpected or improved properties. Here we define the term "multi-component nanoparticles" as hybrid structures composed of two or more condensed nanoscale domains with distinctive material compositions, shapes, or sizes. We reviewed and discussed the designing principles and synthetic strategies to efficiently combine multiple components to form hybrid nanoparticles with a new or improved plasmonic functionality. In particular, it has been quite challenging to precisely synthesize widely diverse multicomponent plasmonic structures, limiting realization of the full potential of plasmonic heterostructures. To address this challenge, several synthetic approaches have been reported to form a variety of different multicomponent plasmonic nanoparticles, mainly based on heterogeneous nucleation, atomic replacements, adsorption on supports, and biomolecule-mediated assemblies. In addition, the unique and synergistic features of multicomponent plasmonic nanoparticles, such as combination of pristine material properties, finely tuned plasmon resonance and coupling, enhanced light-matter interactions, geometry-induced polarization, and plasmon-induced energy and charge transfer across the heterointerface, were reported. In this review, we comprehensively summarize the latest advances on state-of-art synthetic strategies, unique properties, and promising applications of multicomponent plasmonic nanoparticles. These plasmonic nanoparticles including heterostructured nanoparticles and composite nanostructures are prepared by direct synthesis and physical force- or biomolecule-mediated assembly, which hold tremendous potential for plasmon-mediated energy transfer, magnetic plasmonics, metamolecules, and nanobiotechnology.

246 citations

Journal ArticleDOI
Xiang Wang1, Sheng-Chao Huang1, Shu Hu1, Sen Yan1, Bin Ren1 
27 Apr 2020
TL;DR: In this paper, the authors survey the fundamental principles, advantages and limitations of using localized surface plasmon resonance to enhance the Raman signal in PERS and provide an overview of state-of-the-art PERS applications in materials characterization, bioanalysis and the study of surfaces and interfaces.
Abstract: Plasmon-enhanced Raman spectroscopy (PERS), including surface-enhanced Raman spectroscopy, shell-isolated nanoparticle-enhanced Raman spectroscopy and tip-enhanced Raman spectroscopy, has witnessed substantial development over the past 20 years. These techniques can provide fingerprint information on target materials with sensitivities down to the single-molecule level and with sufficient spatial resolution to observe individual vibrational modes. PERS has thus found applications in diverse areas, ranging from bioanalysis to materials characterization. In this Technical Review, we survey the fundamental principles, advantages and limitations of using localized surface plasmon resonance to enhance the Raman signal in PERS. We discuss the issues that influence the sensitivity and interpretation of PERS results and provide an overview of state-of-the-art PERS applications in materials characterization, bioanalysis and the study of surfaces and interfaces. We also troubleshoot common experimental issues, largely based on our own experience. Finally, we conclude by examining future directions and issues to be addressed for the further development of PERS techniques. Plasmon-enhanced Raman spectroscopy (PERS) is a highly sensitive technique that can provide molecular fingerprint information. This Technical Review discusses the fundamental principles, advantages and limitations of PERS, key issues in using PERS and interpreting results, and state-of-the-art applications in materials characterization, bioanalysis and the study of surfaces.

245 citations