Special Issue "Computational and Spectroscopic Studies on Metal Nanoparticles"

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: 31 October 2019.

Special Issue Editor

Prof. Maurizio Muniz-Miranda
E-Mail Website
Guest Editor
Dipartimento di Chimica, Università di Firenze, Via della Lastruccia, 3 - 50019 Sesto Fiorentino, Italy
Interests: materials science, metal nanoparticles, catalytic and biomedical applications

Special Issue Information

Dear Colleagues,

Metal nanoparticles represent a bridge between single atoms and bulk materials, presenting peculiar chemical and optical properties, along with potential applications in many fields, especially in catalysis and biomedicine. Under irradiation with an appropriate electromagnetic wave, the conduction electrons do not oscillate freely because they are trapped in the nanometric size of the metal particles, which exhibit collective excitations called “localized plasmons”. These latter are needed to promote enhancements for both the Raman signal and the fluorescence emission of molecules adhering to the metal surface, when the exciting radiation wavelengths match those of the plasmon bands. Hence, Raman enhancements up to 107 factors are generally observed for molecules adsorbed on silver or gold nanoparticles in the SERS (surface-enhanced Raman scattering) measurements. When, instead, metal particles have sizes below about 2 nm, they do not have metallic properties owing to the existence of discrete electronic energy levels and the loss of overlapping electronic bands. These particles exhibit a typical quantum size behavior, with optical and electronic properties different from those relative to plasmons. Different computational approaches can be employed to analyze the spectroscopic properties of these different systems, mainly by adopting the density functional theory (DFT) and its time-dependent extension (TD-DFT).

Prof. Maurizio Muniz-Miranda
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • metal nanoparticles
  • Raman scattering
  • absorption spectra
  • fluorescence
  • computational approaches
  • (TD)DFT

Published Papers (2 papers)

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Research

Open AccessArticle
Gold Film over SiO2 Nanospheres—New Thermally Resistant Substrates for Surface-Enhanced Raman Scattering (SERS) Spectroscopy
Nanomaterials 2019, 9(10), 1426; https://doi.org/10.3390/nano9101426 - 09 Oct 2019
Abstract
Surface-enhanced Raman scattering (SERS) sensors are constructed from metallic plasmonic nanostructures providing high sensitivity and spectral reproducibility. In many cases, irradiation of the SERS substrate by the laser beam leads to an increase of the local temperature and consequently to thermal degradation of [...] Read more.
Surface-enhanced Raman scattering (SERS) sensors are constructed from metallic plasmonic nanostructures providing high sensitivity and spectral reproducibility. In many cases, irradiation of the SERS substrate by the laser beam leads to an increase of the local temperature and consequently to thermal degradation of metallic nanostructure itself and/or adsorbed analyte. We report here a “bottom-up” technique to fabricate new thermally resistant gold “film over nanosphere” (FON) substrates for SERS. We elaborated the simple and straightforward method of preparation of homogeneously and closely packed monolayer of SiO2 nanoparticles (50 nm in diameter) and covered it by a thin (20 nm) layer of magnetron-sputtered gold. The spectral testing using biologically important molecules (methylene blue, cationic porphyrin, and fungicide 1-methyl-1H-benzimidazole-2-thiol) proved a sensitivity and reproducibility of our AuSiO2 substrates. The main advantage of such SERS-active substrates is high thermal stability and low intensity of background and signal of graphitic carbon. Full article
(This article belongs to the Special Issue Computational and Spectroscopic Studies on Metal Nanoparticles)
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Open AccessArticle
A DFT Approach to the Surface-Enhanced Raman Scattering of 4-Cyanopyridine Adsorbed on Silver Nanoparticles
Nanomaterials 2019, 9(9), 1211; https://doi.org/10.3390/nano9091211 - 28 Aug 2019
Abstract
A Surface-Enhanced Raman Scattering (SERS) spectrum of 4-cyanopyridine (4CNPy) was recorded on silver plasmonic nanoparticles and analyzed by using Density Functional Theory (DFT) calculations. Two simple molecular models of the metal–4CNPy surface complex with a single silver cation or with a neutral dimer [...] Read more.
A Surface-Enhanced Raman Scattering (SERS) spectrum of 4-cyanopyridine (4CNPy) was recorded on silver plasmonic nanoparticles and analyzed by using Density Functional Theory (DFT) calculations. Two simple molecular models of the metal–4CNPy surface complex with a single silver cation or with a neutral dimer (Ag+–4CNPy, Ag2–4CNPy), linked through the two possible interacting sites of 4CNPy (aromatic nitrogen, N, and nitrile group, CN), were considered. The calculated vibrational wavenumbers and intensities of the adsorbate and the isolated species are compared with the experimental Raman and SERS results. The analysis of the DFT predictions and the experimental data indicates that 4CNPy adsorbs preferentially on neutral/charged active sites of the silver nanoparticles through the nitrogen atom of the aromatic ring with a perpendicular orientation. Full article
(This article belongs to the Special Issue Computational and Spectroscopic Studies on Metal Nanoparticles)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Charge transfer in the Surface-Enhanced Raman Spectra of 4-cyanopyridine.
Author: I. López-Tocón* and col.
Affiliation: Department of Physical Chemistry, Faculty of Sciences, University of Málaga, E-29071 Málaga, Spain
Abstract: SERS spectra of 4-cyanopyridine (4CNPy) have been recorded on a nanostructured silver surface at different electrode potentials using the 785 nm laser line and analyzed on the basis of a resonant Raman process involving photoexcited metal (M)-to-molecule (A) charge transfer (CT: M–A + hn → M+–A-) states of the surface complex. The main features are the weak enhancement of the in-plane 8a; vring totally symmetric A1 modes and the appearance of the characteristic bands of pyridine and CN- at negative electrode potentials. In order to explain this behavior, electronic structure calculations of the complex have been carried out of a model of linear silver clusters with different number of atoms (n: 2,3,5,7) and charge (q: 0, +1, -1) bounded to the molecule, [Agn-4CNPY]q complex. Two different M-A complexes have been considered, one linked to the aromatic nitrogen, Ag-N, and other linked to the CN group, Ag-CN. The calculated resonance Raman-CT spectra (SERS-CT) and the vibrational wavenumbers of isolated 4CNPy and of the different complexes obtained from TD-DFT electronic structure calculations are discussed.

Title: Optical Properties of Metallic Nanoparticles: from fundamentals to applications
Authors: Lu Wang, Leonidas Agiotis and Michel Meunier
Abstract: Metallic nanoparticles (NPs) have been rapidly developed recently, because of their unique optical properties based on the interaction between light and metallic nanostructures. In this review, we will discuss the fundamentals of surface plasmonic and demonstrate the important applications based on different optical properties of NPs, including light absorption, scattering and field enhancement. First, Mie theory will be discussed as the main model for understanding the phenomenon of Localized Surface Plasmon Resonance (LSPR). Many extensions of the theory for different factors will be introduced, such as shape, composition, surrounding medium, and surface enhancement effects. Furthermore, we will also provide a brief overview of the fundamentals of the nonlinear optical properties of metallic NPs. Finally, a wide range of applications in the fields of biomedicine, energy and information will be demonstrated in detail, based on the linear optical properties of absorption, scattering and field enhancement but also arising from nonlinear effects such as enhanced harmonics generation, saturation of absorption and frequency mixing. 

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