Colloidal solution of silver nanoparticles for label-free colorimetric sensing of ammonia in aqueous solutions

• Alessandro Buccolieri,
• Antonio Serra,
• Gabriele Giancane and
• Daniela Manno

Beilstein J. Nanotechnol. 2018, 9, 499–507, doi:10.3762/bjnano.9.48

• analysis provides the basis for the production of a colorimetric label-free sensor for ammonia. Overall, surface plasmon resonance increases when ammonia concentration rises, although the functional trend is not the same over the entire investigated ammonia concentration range. Three different ranges have

• particular silver nanoparticles (AgNPs), are often considered for analytical application because of their peculiar optical and electrical properties [13]. The surface plasmon resonance (SPR) properties of metal nanoparticles are considered very useful for the use of colloidal solutions in the field of

• cations and ammonia anions are formed, the formation of Ag nanoparticles is inhibited. Recent results seem to disagree with previous reports about the role of ammonia and show an increase in the plasmon resonance intensity of silver nanoparticles synthesized in the presence of ammonia [23][24]. On the

Nematic liquid crystal alignment on subwavelength metal gratings

• Irina V. Kasyanova,
• Artur R. Geivandov,
• Vladimir V. Artemov,
• Maxim V. Gorkunov and
• Serguei P. Palto

Beilstein J. Nanotechnol. 2018, 9, 42–47, doi:10.3762/bjnano.9.6

• a liquid crystal into a hybrid system is especially interesting as it can result in even more novel and interesting properties. In our recent work, we showed that liquid crystals strongly affect both the plasmon resonance and light polarization properties of subwavelength metal gratings [9

• = 1/3. For this grating both TM and TE-mode FT spectra show pronounced splitting. However, it is known [9] that for the gratings with this geometry there is a plasmon resonance for the TM mode and the transmittance resonance for the TE mode in the spectral range of 500–600 nm. Therefore, the Fabry

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

• Agata Siarkowska,
• Miłosz Chychłowski,
• Daniel Budaszewski,
• Bartłomiej Jankiewicz,
• Bartosz Bartosewicz and
• Tomasz R. Woliński

Beilstein J. Nanotechnol. 2017, 8, 2790–2801, doi:10.3762/bjnano.8.278

• biology [20] due to their optical properties. These properties are related to the interaction of light with electrons on the NP surface. At a specific frequency of light, the oscillation of electrons on the Au NP surface causes an effect called localized surface plasmon resonance. This phenomena can

• result in absorption or scattering of light (Figure 1b). Depending on the size, concentration or shape of the particles, the plasmon resonance can appear at different wavelengths. Moreover, NPs can also provide different properties for the host material. For example, Au NPs have a tendency to lower the

• a behavior in terms of plasmon resonance tuning, i.e., NPs absorbing at a selective wavelength can heat LC molecules, thus shifting the propagation spectrum. A similar effect can be observed in PLCFs, but the mechanism of PBG tuning was thermally induced [33]. However, we believe that the observed

Facile synthesis of silver/silver thiocyanate (Ag@AgSCN) plasmonic nanostructures with enhanced photocatalytic performance

• Xinfu Zhao,
• Dairong Chen,
• Abdul Qayum,
• Bo Chen and
• Xiuling Jiao

Beilstein J. Nanotechnol. 2017, 8, 2781–2789, doi:10.3762/bjnano.8.277

• visible-light irradiation. In addition to the microstructure and high specific surface area, the enhanced photocatalytic activity was mainly caused by the surface plasmon resonance of Ag nanoparticles, and the high stability of AgSCN resulted in the long-term stability of the photocatalyst product

• irradiated for 3 h, indicating the slow reduction of AgSCN under UV irradiation. UV–vis diffuse reflectance spectra of M0, M1, M2, M3, M4, and M5 are shown in Figure 2a. Here, the characteristic absorption of AgSCN appears at 200–350 nm and that from the surface plasmon resonance of Ag particles is above 350

• presence of silver particles not only improves the photocatalytic efficiency, but also enhances the electric field strength around AgSCN due to the surface plasmon resonance, which in turn enhances the optical transition of midgap defect states of AgSCN. All these conditions contribute to the strong

Impact of titanium dioxide nanoparticles on purification and contamination of nematic liquid crystals

• Dmitrii Pavlovich Shcherbinin and
• Elena A. Konshina

Beilstein J. Nanotechnol. 2017, 8, 2766–2770, doi:10.3762/bjnano.8.275

• addition, nanoparticles can induce other new functions in liquid crystals, including improved response time [14][15], surface plasmon resonance [16], and improvements in alignment [17]. The ionic contamination of LCs remains one of the challenges to LC technology. Ionic conductivity negatively affects LC

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

• applications of the optical properties of complex nanoparticle systems usually require a “carrier medium”, i.e., a dielectric matrix transparent in the spectral range of the metal structure’s plasmon resonance. The resulting composite material from the research discussed in this work shows optical properties

• interparticle distance and the properties of the environment [1]. For particles with a diameter of up to a few tens of nanometers that are dispersed in glass, the corresponding wavelength is in the range 520–530 nm [27]. With the increase of the particle size, one observes a red shift of the plasmon resonance

• wavelength. Therefore, the change of the glass color upon heating can be explained by the appearance of Au nanoparticles and their increasing size, i.e., the shift of the plasmon resonance wavelength position, as seen in Figure 2. Nanosecond-pulse processing To determine the conditions for formation of

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

• 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

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

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

• for AgNPs and λmax = 528 nm vs λmax = 540 nm for AuNPs) were observed (Figure 3). This effect is related to the fact that the spectral location of plasmon resonance of single noble metal nanoparticles is dependent on the refractive index (n) of the surrounding medium [28][56]. Coating metal NPs with

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

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

• 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

• 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

• predominantly performed in clinical practice [37]. Other methods, such as chromatography [38][39][40] and surface plasmon resonance [41], are used in fundamental research. Each of these methods of cortisol detection has advantages and drawbacks. Conventional Raman scattering, which is widely used for 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

• 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

• the optical excitation of SPPs, which are ultimately collective optical electromagnetic modes strongly connected to the nanostructure geometry and size [12]. This is because at a metal–dielectric interface, large electric field fluctuations can occur for a plasmon resonance frequency, ωr, that in a

• eigenmodes drive the plasmon resonance and the field enhancements. In fact, the pole accounts for all of the contribution to Green’s functions from the rough surface. Only under small-roughness conditions G0 ≈ Gf, while in general Gf >> G0. Now, we must define the ripple surfaces providing us the profile h(x

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

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

• 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

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

Tunable plasmons in regular planar arrays of graphene nanoribbons with armchair and zigzag-shaped edges

• Cristian Vacacela Gomez,
• Michele Pisarra,
• Mario Gravina and
• Antonello Sindona

Beilstein J. Nanotechnol. 2017, 8, 172–182, doi:10.3762/bjnano.8.18

• correction in mind, we can introduce the inverse dielectric matrix: The zeros in the real part of the macroscopic dielectric function (permittivity) provide the condition for a plasmon resonance to occur, stated as: The imaginary part of the inverse permittivity is proportional to so-called energy loss (EL

• plasmon resonance being blue-shifted by increasing the GNR width (Figure 3a,c). In 11AGNR and 5AGNR, not only the peak position but also the interplay of the interband and intraband plasmon is strongly dictated by the doping level and the GNR width (Figure 3b,d). In 5AGNR, the two modes are well resolved

Streptavidin-coated gold nanoparticles: critical role of oligonucleotides on stability and fractal aggregation

• Roberta D'Agata,
• Pasquale Palladino and
• Giuseppe Spoto

Beilstein J. Nanotechnol. 2017, 8, 1–11, doi:10.3762/bjnano.8.1

• relevant ligands has led to dramatic progresses in both living cells as well as biomolecular diagnostic assays [3][4][5]. In particular, optical sensing exploiting the surface plasmon resonance (SPR) effect has been widely investigated and plays a significant role in biomolecular detection [6][7]. In this