Refractive index sensing and surface-enhanced Raman spectroscopy using silver–gold layered bimetallic plasmonic crystals

• Somi Kang,
• Sean E. Lehman,
• Matthew V. Schulmerich,
• An-Phong Le,
• Tae-woo Lee,
• Stephen K. Gray,
• Rohit Bhargava and
• Ralph G. Nuzzo

Beilstein J. Nanotechnol. 2017, 8, 2492–2503, doi:10.3762/bjnano.8.249

• useful new platform for chemical/spectroscopic sensing. Keywords: finite-difference time-domain; nanoimprint soft lithography; plasmonics; surface plasmon resonance; Introduction Studies of surface plasmons have attracted significant attention due to the diverse range of applications and processes in

• are excited by electromagnetic radiation incident at a metal/dielectric interface. This results in an evanescent decaying electric field that extends from the metal surface for ≈100–200 nm (surface plasmon polaritons), or it can also manifest as a localized surface plasmon resonance at the surface of

• , and nanoscale holes or voids to effect couplings and further obtain stronger electromagnetic fields and higher spatial resolution from localized surface plasmon resonance (LSPR) [18][19][20][21][22][23][24][25][26][27]. Many fabrication methods have been described that provide structures capable of

Laser-assisted fabrication of gold nanoparticle-composed structures embedded in borosilicate glass

• Nikolay Nedyalkov,
• Mihaela Koleva,
• Nadya Stankova,
• Rosen Nikov,
• Mitsuhiro Terakawa,
• Yasutaka Nakajima,
• Lyubomir Aleksandrov and
• Reni Iordanova

Beilstein J. Nanotechnol. 2017, 8, 2454–2463, doi:10.3762/bjnano.8.244

• , the color of the irradiated areas changed to pink, with a corresponding well-defined peak in the absorbance spectrum. We relate this effect to the formation of gold nanoparticles with optical properties defined by plasmon excitation. Their presence was confirmed by high-resolution TEM analysis. No

• an electromagnetic field with these objects are defined by the efficiency of the plasmon excitation (i.e., collective oscillations of the free electrons at a specific frequency defined by the properties of the metal and the surrounding medium) [1]. On resonance, when the electromagnetic field

• frequency equals that of the plasmon, the optical properties of the nanoparticles drastically change. The extinction coefficient is strongly enhanced, and its value may exceed the off-resonance extinction coefficient value by orders of magnitude [2]. While at the turn of the century research interest was

Au nanostructure fabrication by pulsed laser deposition in open air: Influence of the deposition geometry

• Rumen G. Nikov,
• Anna Og. Dikovska,
• Nikolay N. Nedyalkov,
• Georgi V. Avdeev and
• Petar A. Atanasov

Beilstein J. Nanotechnol. 2017, 8, 2438–2445, doi:10.3762/bjnano.8.242

• in the transmission spectra with minimum at ≈520 nm. The presence of this feature in the transmission could be attributed to a plasmon excitation in the nanostructures. The deposition using geometry 4 resulted in an almost flat spectrum with the lowest transmission (<3%) and no clear plasmon behavior

• nanostructures considered result from the interplay of complex phenomena arising from the complex nanoparticle-ensemble morphology of the structures as no individual nanoparticles are present. The pronounced expression and definition of a plasmon resonance band is thus hindered. In such a case, the optical

• properties are defined by the collective effects (as multiple scattering and plasmon coupling) of an electromagnetic field interacting with nanoparticle ensembles. This leads to a broadening of the resonance band, where the optical properties of a single nanoparticle are not expressed. To examine the

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

• glass. A further advantage is that laser light can pass through the polymer substrate and reach the nanoparticle layer to activate the plasmon resonance, which generates the enormous SERS enhancement. A SERS substrate with good transparency and flexibility was prepared as a self-assembly of gold

Ta₂N₃ nanocrystals grown in Al₂O₃ thin layers

• Krešimir Salamon,
• Maja Buljan,
• Iva Šarić,
• Mladen Petravić and
• Sigrid Bernstorff

Beilstein J. Nanotechnol. 2017, 8, 2162–2170, doi:10.3762/bjnano.8.215

• light to nano-scale structures via local surface plasmon resonance (LSPR) [1]. LSPR produces a strong near-field enhancement and a local heating [2][3], which are considered to be promising in several applications ranging from surface-enhanced Raman scattering [4], to catalysis [5] and heat-assisted

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• ). For two of the investigated nanowires, our values are in good agreement with a recent result (≈31 cm2/Vs) in p-type Si-doped GaAs nanowires, obtained by measuring the plasmon–phonon interactions using transmission Raman spectroscopy [59] and, on average, clearly higher than the reported value (0.417

Synthesis and characterization of noble metal–titania core–shell nanostructures with tunable shell thickness

• Bartosz Bartosewicz,
• Marta Michalska-Domańska,
• Malwina Liszewska,
• Dariusz Zasada and
• Bartłomiej J. Jankiewicz

Beilstein J. Nanotechnol. 2017, 8, 2083–2093, doi:10.3762/bjnano.8.208

• , Kaliskiego 2 Str. 00-908 Warsaw, Poland 10.3762/bjnano.8.208 Abstract Core–shell nanostructures have found applications in many fields, including surface enhanced spectroscopy, catalysis and solar cells. Titania-coated noble metal nanoparticles, which combine the surface plasmon resonance properties of the

• great potential for use in these applications [18][19]. Surface plasmon resonance properties of gold and silver NPs can increase the optical absorption of titania and extend its absorption band to the visible light region. Such CSNs could allow one of the most important limitations in broader use of

• titania to be overcome: the limitation of photocatalytic capability to UV light (λ < 400 nm). In addition, they may serve as a precursor for plasmon-sensitized colloidal perovskites, which are materials of great interest for solar cell applications [20]. The limiting factor in the broader use of Ag@TiO2

Imidazolium-based ionic liquids used as additives in the nanolubrication of silicon surfaces

• Patrícia M. Amorim,
• Ana M. Ferraria,
• Rogério Colaço,
• Luís C. Branco and
• Benilde Saramago

Beilstein J. Nanotechnol. 2017, 8, 1961–1971, doi:10.3762/bjnano.8.197

• (S 2p3/2 + S 2p1/2), which is superposed to the Si 2s plasmon loss. Comparison was, therefore, based on the S 2s peaks. In both samples, the signal to noise ratio is very poor (Figure 7b). Anyway, the smoothed data (full black lines) show different S 2s peaks in the sample treated with PEG + [EMIM

Methionine-mediated synthesis of magnetic nanoparticles and functionalization with gold quantum dots for theranostic applications

• Arūnas Jagminas,
• Agnė Mikalauskaitė,
• Vitalijus Karabanovas and
• Jūrate Vaičiūnienė

Beilstein J. Nanotechnol. 2017, 8, 1734–1741, doi:10.3762/bjnano.8.174

• at 291 nm is observed. The UV–vis absorption spectrum of the solution containing the gold species collected from the surface of the cobalt ferrite NPs (Figure 3, plot 3) exhibits two absorption shoulders at 522 and 377 nm. The former seems to be originated from the surface plasmon absorption of

Near-infrared-responsive, superparamagnetic Au@Co nanochains

• Varadee Vittur,
• Arati G. Kolhatkar,
• Shreya Shah,
• Irene Rusakova,
• Dmitri Litvinov and
• T. Randall Lee

Beilstein J. Nanotechnol. 2017, 8, 1680–1687, doi:10.3762/bjnano.8.168

• nanoparticles not only renders the nanoparticles biocompatible but also gives rise to distinct optical properties [18][19]. Noble metal nanoparticles, such as gold and silver, possess the unique property of surface plasmon resonance (SPR); the latter exhibit a strong extinction band in the visible region [19

• arising from the difference between their reduction potentials. Cobalt cores were oxidized by H+ from aqueous HAuCl4 solution until Co nanoparticles were completely consumed, which led to the formation of the hollow gold nanostructures. The surface plasmon resonance of these particles appeared at 628 nm

• related nanostructures [28][29][30]. This considerable increase can be attributed to the formation of both the hollow interior and the chain structure in the present materials. Previous research on Au and Ag nanochains demonstrated that the plasmon resonance of two interacting particles undergoes a red

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

Fixation mechanisms of nanoparticles on substrates by electron beam irradiation

• Daichi Morioka,
• Tomohiro Nose,
• Taiki Chikuta,
• Kazutaka Mitsuishi and
• Masayuki Shimojo

Beilstein J. Nanotechnol. 2017, 8, 1523–1529, doi:10.3762/bjnano.8.153

• been attracting attention because these arrays and patterns offer unique electrical and optical properties. One of the applications of such nanostructure arrays is plasmonic waveguides, in which the energy of light propagates because of the localized surface plasmon resonance (LSPR) effect [1][2]. In

• particular, arrays of gold or silver nanostructures can be used for such waveguides, as nanostructures made of these materials interact with visible light. Such LSPR structures would make the development of smaller optical circuits and devices possible. Plasmon propagation through nanowires or rows of

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls

• Carlos Angulo Barrios and
• Víctor Canalejas-Tejero

Beilstein J. Nanotechnol. 2017, 8, 1231–1237, doi:10.3762/bjnano.8.124

• previous work [11], the SU-8 nanopillar array reflectance exhibits two dips: at λ ≈ 640 nm, due to a metal-assisted, guided mode resonance (MaGMR), and at λ ≈ 840 nm, due to a surface plasmon polariton (SPP). Both of these dips are related to the Al layer (Si substrate coating) of thickness 100 nm on which

• field (Ex) and y-component of the magnetic field (Hy) at the reflectance peak (λ = 700 nm) are shown in Figure 4. Ex and Hy are enhanced and localized at the edges and on top of the metal disk, respectively, suggesting the excitation of a localized surface plasmon resonance (LSPR). On another hand, the

Surface-enhanced Raman spectroscopy of cell lysates mixed with silver nanoparticles for tumor classification

• Mohamed Hassoun,
• Iwan W.Schie,
• Tatiana Tolstik,
• Sarmiza E. Stanca,
• Christoph Krafft and
• Juergen Popp

Beilstein J. Nanotechnol. 2017, 8, 1183–1190, doi:10.3762/bjnano.8.120

• absorption band of silver (Ag) nanoparticles corresponds to the maximum of the plasmon resonance which is near 415 nm (Figure 1a). Shifting the plasmon resonance of our nanoparticles to the near-IR spectral region was achieved by aggregation using potassium chloride (KCl). When nanoparticles aggregate, they

• become electronically coupled, which results in a change of the surface plasmon resonance compared to individual particles. Figure 1b shows the effect of adding KCl to Ag nanoparticles on the optical absorption characteristics. The aggregated nanoparticles have a broad absorption band that allowed for

Optical response of heterogeneous polymer layers containing silver nanostructures

• Miriam Carlberg,
• Florent Pourcin,
• Olivier Margeat,
• Judikaël Le Rouzo,
• Gérard Berginc,
• Rose-Marie Sauvage,
• Jörg Ackermann and
• Ludovic Escoubas

Beilstein J. Nanotechnol. 2017, 8, 1065–1072, doi:10.3762/bjnano.8.108

• wavelength range. The optical properties of these metallic NPs are induced by localized surface plasmon resonances, which are size, shape, material and environment dependent [7]. At the localized surface plasmon resonance wavelengths, the conduction electrons of the NPs oscillate coherently, which induces an

• control the absorption of thin film layers by embedding different NPs. When included in polymer thin film layers (such as poly(vinylpyrrolidone) (PVP)), the plasmon resonance wavelengths of the NPs are red-shifted with respect to the resonance wavelengths in water. This environment dependence can easily

Nanoantenna-assisted plasmonic enhancement of IR absorption of vibrational modes of organic molecules

• Alexander G. Milekhin,
• Olga Cherkasova,
• Sergei A. Kuznetsov,
• Ilya A. Milekhin,
• Ekatherina E. Rodyakina,
• Alexander V. Latyshev,
• Sreetama Banerjee,
• Georgeta Salvan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2017, 8, 975–981, doi:10.3762/bjnano.8.99

• . Keywords: cobalt phthalocyanine; cortisol; localized surface plasmon resonance; metal nanoantennas; Raman scattering; surface-enhanced infrared absorption (SEIRA); Introduction Organic semiconductors have been extensively investigated during the past few decades due to their wide range of applications in

• surface plasmon energy of the nanoantennas to the energy of the molecular vibrations. Along with SEIRA, SERS is also traditionally used to study the vibrational spectra of various organic and biological substances [18], which may be present in very low quantities down to single molecules [19]. Raman

• can be explained by the resonant SERS effect, as the energy of the local surface plasmon resonance (LSPR) of nanoclusters is located in the red spectral region, which is in resonance with the excitation energy. In the case of nanoantennas, the energy of longitudinal LSPR modes polarized along the

Near-field surface plasmon field enhancement induced by rippled surfaces

• Mario D’Acunto,
• Francesco Fuso,
• Ruggero Micheletto,
• Makoto Naruse,
• Francesco Tantussi and
• Maria Allegrini

Beilstein J. Nanotechnol. 2017, 8, 956–967, doi:10.3762/bjnano.8.97

• , Yokohama, Japan Harvard Medical School, 64 Sydney Street, Suite 170, Cambridge, 02139 MA, USA, Network System Research Institute, National Institute of Information and Communications Technology, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795, Japan 10.3762/bjnano.8.97 Abstract The occurrence of plasmon

• of local surface patterns in the tuning of these resonances as a function of wavelength and electric field polarization. The effect of nanoscale roughness on the surface plasmon polaritons of randomly patterned gold films is numerically investigated. The field enhancement and relation to specific

• scanning near-field optical microscopy. Keywords: aperture scanning near-field optical microscopy; gold rippled surface; localized hot spots; metal–dielectric−metal nanogaps; surface plasmon resonance; Introduction Metal nanostructures capable of producing localized surface plasmon polaritons (SPPs) are

Selective detection of Mg²⁺ ions via enhanced fluorescence emission using Au–DNA nanocomposites

• Tanushree Basu,
• Khyati Rana,
• Niranjan Das and
• Bonamali Pal

Beilstein J. Nanotechnol. 2017, 8, 762–771, doi:10.3762/bjnano.8.79

• from the observed changes in the optical absorption, plasmon band, zeta potential, DLS particle size distribution, as well as TEM and AFM surface morphology analysis. Circular dichroism studies also revealed that DNA-functionalized AuNP binding caused a conformational change in the DNA structure. Due

• various DNA detection schemes. The high sensitivity of the plasmon spectra towards the particle size and the local dielectric environment also offers new methods for the detection of free DNA or other biomolecules [2], where the detection signal is exclusively based on the color changes during assay or

• absorption of different bare and DNA-modified AuNPs (AuNS-1, AuNS-2, AuNS-3 and AuNS-4) is shown in Supporting Information File 1, Figure S1. It was found that due to their size dependency [17], the plasmon band shift (summarized in Supporting Information File 1, Table S1) occurred towards longer wavelengths

α-((4-Cyanobenzoyl)oxy)-ω-methyl poly(ethylene glycol): a new stabilizer for silver nanoparticles

• Jana Lutze,
• Miguel A. Bañares,
• Marcos Pita,
• Andrea Haase,
• Andreas Luch and
• Andreas Taubert

Beilstein J. Nanotechnol. 2017, 8, 627–635, doi:10.3762/bjnano.8.67

• ][53][54]. Figure 2D shows that the UV–vis spectra exhibit significant changes upon treatment of the nanoparticles with the polymer. Initially the samples exhibit a single, rather broad plasmon band at 385 nm. After modification with the polymer, two bands at 393 and 545 nm are visible. Stability of

Thin SnO_x films for surface plasmon resonance enhanced ellipsometric gas sensing (SPREE)

• Daniel Fischer,
• Andreas Hertwig,
• Uwe Beck,
• Volkmar Lohse,
• Detlef Negendank,
• Martin Kormunda and
• Norbert Esser

Beilstein J. Nanotechnol. 2017, 8, 522–529, doi:10.3762/bjnano.8.56

• the problems of cross sensitivity of the MOS concept. Results: Undoped tin oxide (SnOx) and iron doped tin oxide (Fe:SnOx) thin add-on films were prepared by magnetron sputtering on the top of the actual surface plasmon resonance (SPR) sensing gold layer. The films were tested for their sensitivity to

• several gas species in the surface plasmon resonance enhanced (SPREE) gas measurement. It was found that the undoped tin oxide (SnOx) shows higher sensitivities to propane (C3H8) then to carbon monoxide (CO). By using Fe:SnOx, this relation is inverted. This behavior was explained by a change of the

• sensing devices with different coated SPREE sensors. Keywords: doped tin oxide; ellipsometry; gas sensing; surface plasmon resonance; thin films; transparent conductive oxides; Introduction Gas sensors are an important tool for example in the fields of process monitoring, workplace safety or

Self-assembly of silicon nanowires studied by advanced transmission electron microscopy

• Marta Agati,
• Guillaume Amiard,
• Vincent Le Borgne,
• Paola Castrucci,
• Richard Dolbec,
• Maurizio De Crescenzi,
• My Alì El Khakani and
• Simona Boninelli

Beilstein J. Nanotechnol. 2017, 8, 440–445, doi:10.3762/bjnano.8.47

• . Energy-filtered TEM (EFTEM) images, acquired in correspondence to the Si plasmon loss (17 eV) and SiO2 plasmon loss (23 eV), display a common core–shell Si–SiO2 internal structure for both the NSs and the NWs (see Figure 1b and Figure 1c). Further EFTEM investigations conducted on hundreds of NWs

• Visualiser Kai software was used for visualization. (a) Typical SEM image showing the morphology of the as-collected sample; EFTEM images obtained at (b) the Si plasmon loss (17 eV) and (c) the SiO2 plasmon loss (23 eV), revealing the Si–SiO2 core–shell structure and the structural continuity between the Si

Fabrication of black-gold coatings by glancing angle deposition with sputtering

• Alan Vitrey,
• Rafael Alvarez,
• Alberto Palmero,
• María Ujué González and
• José Miguel García-Martín

Beilstein J. Nanotechnol. 2017, 8, 434–439, doi:10.3762/bjnano.8.46

• properties of gold nanostructures are dominated by the existence of localized surface plasmon resonances (LSPRs), and that these LSPRs induce enhanced scattering, it is reasonable to assume that such low reflectance is due to the combined effect of the LSPRs and the light trapping associated with multiple

Comparison of four methods for the biofunctionalization of gold nanorods by the introduction of sulfhydryl groups to antibodies

• Xuefeng Wang,
• Zhong Mei,
• Yanyan Wang and
• Liang Tang

Beilstein J. Nanotechnol. 2017, 8, 372–380, doi:10.3762/bjnano.8.39

• biomedicine, including biosensing [1][2][3], photothermal therapy [4][5][6], molecular imaging [7][8], and controlled drug delivery [5][9] because of their distinct optical properties, i.e., high refractive index sensitivity and a tunable longitudinal plasmon band by varying the aspect ratio [10][11]. However

• containing 1% BSA (pH 7.4) as described previously in our work [17], to eliminate non-specific binding and adsorption. GNRs exhibit a unique optical transduction because of their localized surface plasmon resonance (LSPR). The particular sensitivity of the longitudinal plasmon band could induce a significant

• change in longitudinal plasmon wavelength when the refractive index alteration was elicited by target binding to the GNRs surface [10][14]. Figure 2 shows the absorption spectra of GNRs after conjugating with various thiolated anti-IgG. This conjugation resulted in a red shift in the longitudinal peak of

Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO₂ nanoparticles on a Si substrate

• Urmas Joost,
• Andris Šutka,
• Meeri Visnapuu,
• Aile Tamm,
• Meeri Lembinen,
• Mikk Antsov,
• Kathriin Utt,
• Krisjanis Smits,
• Ergo Nõmmiste and
• Vambola Kisand

Beilstein J. Nanotechnol. 2017, 8, 229–236, doi:10.3762/bjnano.8.25

• was previously utilized both in localized surface plasmon resonance (LSPR) devices and porous Bragg stacks [17]. As mentioned before, the NPs in our samples are covered with PTSA. This functional coating ensures selectivity and different responses to different VOCs. Figure 6 shows that the proposed NP

Influence of hydrofluoric acid treatment on electroless deposition of Au clusters

• Rachela G. Milazzo,
• Antonio M. Mio,
• Giuseppe D’Arrigo,
• Emanuele Smecca,
• Alessandra Alberti,
• Gabriele Fisichella,
• Filippo Giannazzo,
• Corrado Spinella and
• Emanuele Rimini

Beilstein J. Nanotechnol. 2017, 8, 183–189, doi:10.3762/bjnano.8.19

• shown quite interesting applications in the fields of Si nanowire (SiNW) catalysis [1][2][3], metal-assisted etching (MAE) [4] or even as electrical contacts in standard miniaturized devices [5]. Their ability to display enhanced surface plasmon resonance (SPR) at optical frequencies makes them