Combining physical vapor deposition structuration with dealloying for the creation of a highly efficient SERS platform

• Adrien Chauvin,
• Walter Puglisi,
• Damien Thiry,
• Cristina Satriano,
• Rony Snyders and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2023, 14, 83–94, doi:10.3762/bjnano.14.10

• use of Taro leaves or rose petals as substrates for silver PVD coating leads to a SERS detection limit down to 10−8 mol·L−1 and 10−9 mol·L−1, respectively, for rhodamine 6G (R6G) [55][56]. Moreover, the use of silver-coated paper as a SERS substrate reveals a detection limit down to 10−10 mol·L−1 for

• R6G [57]. Besides an easy synthesis and a good detection limit, these substrates cannot be cleaned and reused. In the case of nanoporous silver, the reusability of the structure for SERS detection has already been reported [1]. Conclusion The development of an easy strategy to engineer efficient SERS

Revealing local structural properties of an atomically thin MoSe₂ surface using optical microscopy

• Lin Pan,
• Peng Miao,
• Anke Horneber,
• Alfred J. Meixner,
• Pierre-Michel Adam and
• Dai Zhang

Beilstein J. Nanotechnol. 2022, 13, 572–581, doi:10.3762/bjnano.13.49

• , including graphene and 2D-TMDC materials, are unique platforms for SERS investigations based on the chemical mechanism [21]. Recently, enhanced Raman signals of rhodamine 6G (R6G) molecules on an oxygen plasma-treated MoS2 flake were reported, because the symmetry of the R6G molecule can be modified through

• the interaction with local dipoles in plasma-treated MoS2 [22]. Additionally, the electronic band structure of MoS2 can be significantly modified after oxygen incorporation into MoS2. The charge transfer from the valence band of partially oxidized MoS2 to the LUMO of R6G can be tuned in resonance with

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

• Ioana Marica,
• Fran Nekvapil,
• Maria Ștefan,
• Cosmin Farcău and
• Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

• detection of dopamine, an enhancement factor of Au–ZnO NRs greater than 1.2 × 104 was obtained. The 3D SERS substrates based on Ag/ZnO/Au structures showed a higher SERS enhancement factor of 1 × 1010 and a limit of detection (LOD) down to 10−16 for rhodamine 6G (R6G) [68]. In this case, the charge transfer

• detection of 1.49 × 10−13 and 9.99 × 10−12 were reported by Kumar et al. for 4-nitrophenol (4-NP) and R6G, respectively, adsorbed onto a ZnO multipod suspension containing Ag nanospheres [69]. Increasing the sputtering time leads to an increase of the Au NPs size and a decrease of the interparticle gap

• –shell metal–ZnO nanocomposites have shown new exciting properties and even metal-enhanced fluorescence for dyes mixed with the NPs. [20] demonstrated MEF for Ag–ZnO using rhodamine 6G (R6G), prepared through a simple chemical reduction method and deposition of the nanoscale ZnO layer on the surface of

Fabrication of nano/microstructures for SERS substrates using an electrochemical method

• Jingran Zhang,
• Tianqi Jia,
• Xiaoping Li,
• Junjie Yang,
• Zhengkai Li,
• Guangfeng Shi,
• Xinming Zhang and
• Zuobin Wang

Beilstein J. Nanotechnol. 2020, 11, 1568–1576, doi:10.3762/bjnano.11.139

• electrochemical method, three-dimensional arrayed nanopore structures are machined onto a Mg surface. The structured Mg surface is coated with a thin gold (Au) film, which is used as a surface-enhanced Raman scattering (SERS) substrate. A rhodamine 6G (R6G) probe molecule is used as the detection agent for the

• . Subsequently, nanoholes were transferred onto the glass surface using the peeling template method and R6G molecules (10−6 mol·L−1) were used with the substrate for detection. Au nanostructures of different shapes and sizes (including grating, disk, and pyramid structures) have also been fabricated using EBL

• and reactive ion etching methods [25]. The Raman intensities of R6G and 4-mercaptopyridine molecules were measured by using different substrates. In addition, the Raman intensity of R6G on the pyramid structures was higher than that of R6G on the other structures in the experiment, and the enhancement

Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

• Jingran Zhang,
• Tianqi Jia,
• Yongda Yan,
• Li Wang,
• Peng Miao,
• Yimin Han,
• Xinming Zhang,
• Guangfeng Shi,
• Yanquan Geng,
• Zhankun Weng,
• Daniel Laipple and
• Zuobin Wang

Beilstein J. Nanotechnol. 2019, 10, 2483–2496, doi:10.3762/bjnano.10.239

• . The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor using malachite green molecules was found to reach 5.089 × 109, which demonstrates that the production method is a simple, reproducible and low-cost method for machining a highly

• sensitive, hierarchical SERS substrate. Keywords: Ag nanoparticles; hierarchical substrates; malachite green molecules; nanoindentation; nanostructures; R6G; SERS; Introduction Surface-enhanced Raman scattering (SERS) has triggered significant research interest due to its suitability as an analytical tool

• of R6G molecules on the arrayed inverted pyramid cavities of Cu(110) substrates with different feeds. In the present work, a new method including an indentation process and chemical redox reaction is achieved to machine the hierarchical SERS substrates. Complex arrayed micro/nanocavities are formed

A silver-nanoparticle/cellulose-nanofiber composite as a highly effective substrate for surface-enhanced Raman spectroscopy

• Yongxin Lu,
• Yan Luo,
• Zehao Lin and
• Jianguo Huang

Beilstein J. Nanotechnol. 2019, 10, 1270–1279, doi:10.3762/bjnano.10.126

• (Ag-NP/cellulose-NF) showed a very good SERS performance. In the optimized case, the detection limit of Rhodamine 6G (R6G) was as low as 1 × 10−16 M (sub-attomolar level) with just a small droplet of solution needed (10 µL). This is superior to some of the reported works mentioned above [55][56][57

• good agreement with the afore-mentioned characterizations. SERS performance of the Ag-NP/cellulose-NF substrate The performance of the Ag-NP/cellulose-NF composite sheets as SERS substrates was investigated by using Rhodamine 6G (R6G, inset of Figure 4a) as probe molecule. Neither the filter paper

• itself nor the pure Ag-NP/cellulose-NF substrate gave any spectral peak in the wavenumber region measured (Supporting Information File 1, Figure S5). R6G is employed as the model analyte due to its strong affinity to silver particles and its distinct Raman fingerprint [53]. All samples gave the

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• . Finally, a spatial resolution of ≈5 nm is shown on TERS maps of rhodamine 6G (R6G) sub-monolayers absorbed onto gold monocrystals. Experimental Gold wires (125 μm diameter, Advent AU517311, high purity 99.99%, temper hard) are etched in a 10 mL solution 1:1 v/v of fuming hydrochloric acid (>37 wt %) and

• on the shaft (red line). Typical laser powers are 1.0–2.5 mW and integration times are 0.5–1.0 s per pixel. TERS spectra of dyes, pigments and biomolecules The tips have been applied to evaluate the spectra of analyze standard dye molecules such as rhodamine 6G (R6G), crystal violet (CV), methylene

• order to remove the molecules excess. Finally, they are dried under a nitrogen flux. Figure 7 shows the TERS spectra acquired on R6G at 10−4 M (a), CV at 10−5 M (b), MB at 10−5 M (c) and AZ-s at 10−3 M (d). The TERS spectra highlight a high contrast with respect to the signal acquired when the tip is

The role of adatoms in chloride-activated colloidal silver nanoparticles for surface-enhanced Raman scattering enhancement

• Nicolae Leopold,
• Andrei Stefancu,
• Krisztian Herman,
• István Sz. Tódor,
• Stefania D. Iancu,
• Vlad Moisoiu and
• Loredana F. Leopold

Beilstein J. Nanotechnol. 2018, 9, 2236–2247, doi:10.3762/bjnano.9.208

• of chloride was reported in several studies. Futamata and Maruyama showed that Cl− ions induce the electronic interaction between silver nanoparticles and rhodamine 6G (R6G), leading to intense SERS spectra [28]. Doering and Nie highlighted the activating effect of halide ions such as Cl−, Br− or I

• concentration range between 10−3–10−2 M and Mg2+ or Ca2+ in concentrations between 10−4–10−3 M. In order to study the effect of the Cl− surface density and dye concentration on Raman enhancement, we performed a series of SERS studies on R6G in the 10−7–10−11 M concentration range using Cl-AgNPs and cit-AgNPs

• , the details of which are included in Supporting Information File 1 (Figures S3 and S4). In the case of R6G analyzed with as-synthesized Cl-AgNPs, the limit of detection was 10−8 M (Supporting Information File 1, Figure S3A, spectrum b). In other words, the number of Cl− SERS-active sites on the silver

Facile chemical routes to mesoporous silver substrates for SERS analysis

• Elina A. Tastekova,
• Alexander Y. Polyakov,
• Anastasia E. Goldt,
• Alexander V. Sidorov,
• Alexandra A. Oshmyanskaya,
• Irina V. Sukhorukova,
• Dmitry V. Shtansky,
• Wolgang Grünert and
• Anastasia V. Grigorieva

Beilstein J. Nanotechnol. 2018, 9, 880–889, doi:10.3762/bjnano.9.82

• spectroscopy of rhodamine 6G (R6G) was performed using 5 μL droplets and the concentration range of the analyte was 10−8–10−6 M. The corresponding Raman spectra for R6G deposited onto pristine silver oxide samples contained no signal from the model analyte but only noisy background, indicating luminescence

• 10−8 M concentration are rather poor and only contained the known weak C–C stretching modes at 1508 cm−1 (Figure 4b), while all other peaks of R6G vanished or broadened to form a significant background contribution. Feasibly, the effect of a noisy background is due to the diverse types of pores in

• the materials when the derived surface serves as a source of surpassing scattering. The typical SERS spectra of R6G for 10−7 M and 10−6 M analyte concentrations show intensive stretching vibrations of carbon aromatic skeleton of the molecule at 1362(s), 1508(s), 1580(m), 1601(s), and 1650 (s) (Figure

Fabrication of gold-coated PDMS surfaces with arrayed triangular micro/nanopyramids for use as SERS substrates

• Jingran Zhang,
• Yongda Yan,
• Peng Miao and
• Jianxiong Cai

Beilstein J. Nanotechnol. 2017, 8, 2271–2282, doi:10.3762/bjnano.8.227

• the structures were successfully transferred to a polydimethylsiloxane (PDMS) surface using a reverse nanoimprinting approach. The structured PDMS surface is coated with a thin Au film, and the final substrate is demonstrated as a surface-enhanced Raman spectroscopy (SERS) substrate. Rhodamine 6G (R6G

• 1362 cm−1 R6G peak on the structured Au-film-coated PDMS substrate is about 8 times higher than the SERS tests on a commercial substrate (Q-SERS). A SERS enhancement factor ranging from 7.5 × 105 to 6 × 106 was achieved using the structured Au-film-coated PDMS surface, and it was demonstrated that the

• rhodamine 6G (R6G) were detected as test analytes [17]. The micro/nanostructures of a blue butterfly wing were used as a template, and a SERS substrate was produced and utilized to detect rhodamine dye for the elimination of organic pollutants [19]. Additionally, pyramidal array structures on conventional

Controlled graphene oxide assembly on silver nanocube monolayers for SERS detection: dependence on nanocube packing procedure

• Martina Banchelli,
• Bruno Tiribilli,
• Roberto Pini,
• Luigi Dei,
• Paolo Matteini and
• Gabriella Caminati

Beilstein J. Nanotechnol. 2016, 7, 9–21, doi:10.3762/bjnano.7.2

• intensity of the R6G probe and enhancement factor are obtained for the large surface densities, i.e., 32.5 AgNC/μm2. Absorbance spectra for the AgNC arrays obtained with procedure B were tentatively acquired for glass and silicon oxide substrates, respectively. Typical results on glass (see Supporting

Properties of plasmonic arrays produced by pulsed-laser nanostructuring of thin Au films

• Katarzyna Grochowska,
• Katarzyna Siuzdak,
• Peter A. Atanasov,
• Carla Bittencourt,
• Anna Dikovska,
• Nikolay N. Nedyalkov and
• Gerard Śliwiński

Beilstein J. Nanotechnol. 2014, 5, 2102–2112, doi:10.3762/bjnano.5.219

• -nanostructured, thin Au films and of reference samples (SiO2 glass and continuous Au film) covered with a dried solution of ≈10−5 M R6G in ethanol are shown in Figure 6. The spectra were recorded with a micro-Raman spectrometer (InVia, Renishaw) with excitation wavelengths of 514 and 785 nm and a microscope

• (see distributions in Figure 5) [31]. The effect originates in the difference of surface coverage by the R6G dried film and by the Au nanoparticles. The latter is low and does not exceed 30%, while the dye film covers the entire nanoarray surface together with the inter-particle areas. In consequence

• , a large part of the illuminating radiation is absorbed by the dye molecules and does not contribute to the scattering signal. Moreover, the strong absorption band of R6G at 530 nm matches nearly perfectly with the broad plasmon band at around 546 nm (FWHM ≈110 nm). This leads to a decrease of the

Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• (Varian, Palo Alto, CA) and excitation and emission spectra were recorded on a Fluorolog-3 spectro-fluorometer (HORIBA Jobin Yvon, Edison, NJ). Quantum yields were determined relative to rhodamine 6G (R6G) [62]. Size and charge determination Hydrodynamic radii of the ligand-stabilized QDs (dissolved in