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

• tips are TERS-active, while 50% of the tips have a radius of curvature smaller than 35 nm. Light emission from the tip apex Tightly coupled plasmonic metals, such as nanorods dimers [51], nanocubes on surfaces [52], or TERS tips in contact with surfaces [53][54], emit light over a broad continuum, even

Size-selected Fe₃O₄–Au hybrid nanoparticles for improved magnetism-based theranostics

• Maria V. Efremova,
• Yulia A. Nalench,
• Eirini Myrovali,
• Anastasiia S. Garanina,
• Ivan S. Grebennikov,
• Polina K. Gifer,
• Maxim A. Abakumov,
• Marina Spasova,
• Makis Angelakeris,
• Alexander G. Savchenko,
• Michael Farle,
• Natalia L. Klyachko,
• Alexander G. Majouga and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2018, 9, 2684–2699, doi:10.3762/bjnano.9.251

• dimers (Fe3O4–Au [81] and Fe2O3–Au [82]), where the heating efficiency is optimized at diameters of about 23 nm, and SLP values up to 1330 ± 20 W·g−1 (300 kHz, 30 mT) are reported. This high SLP value, however, is questionable, since the heating curve of this sample provided in the supplementary

Silencing the second harmonic generation from plasmonic nanodimers: A comprehensive discussion

• Jérémy Butet,
• Gabriel D. Bernasconi and
• Olivier J. F. Martin

Beilstein J. Nanotechnol. 2018, 9, 2674–2683, doi:10.3762/bjnano.9.250

• report a comprehensive discussion of the SHG from gold dimers focusing on the implications of the silencing effect. The linear and second harmonic responses of the dimers have been computed using a surface integral equations method. The first dimers considered in this article are made of cylindrical

• nanorods with hemispherical extremities and various gap distances. In order to unveil the role of the silencing effect, computations of the SHG considering only the surface second harmonic sources on specific parts of the dimers are also presented. The meshes describing the dimers are then slightly

• deformed to mimic the presence of defects on the nanorod surfaces. Finally, gold dimers made of rectangular arms are considered. Numerical Methods The linear optical response was calculated using a surface integral formulation [23][24]. All the nanostructures are embedded in a homogeneous medium with

Non-agglomerated silicon–organic nanoparticles and their nanocomplexes with oligonucleotides: synthesis and properties

• Asya S. Levina,
• Marina N. Repkova,
• Nadezhda V. Shikina,
• Zinfer R. Ismagilov,
• Svetlana A. Yashnik,
• Dmitrii V. Semenov,
• Yulia I. Savinovskaya,
• Natalia A. Mazurkova,
• Inna A. Pyshnaya and
• Valentina F. Zarytova

Beilstein J. Nanotechnol. 2018, 9, 2516–2525, doi:10.3762/bjnano.9.234

• splitting of the absorption band at 1085 cm−1, which corresponds to asymmetric valence vibrations of the Si–O bond, into two bands at 1100 cm−1 and 1000 cm−1 is typical for polymer structures with Si–O–Si fragments and indicates the presence of at least dimers in the Si–NH2 nanoparticles. The bands at 3058

• value, as expected, became negative (Table 1). A rough estimation of the [–Si(OH)(C3H6NH2)O–] monomer volume based on the chemical bond lengths (≈0.4 nm3) allowed us to assume that the Si–NH2 nanoparticle (≈0.8 nm3) contains about two monomer units, i.e., dimers. The hydrodynamic diameter of the Si–NH2

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• response is governed by plasmonic mode coupling, are symmetric dimers formed of spherical nanoparticles. Often these structures are used as a model system to understand the impact of hot spots in more complex systems [31][32]. However, the multiplicity of modes, and with that, the ability for tailoring the

• ). Usually, this end point of the antenna is not considered in common SERS applications due to the one to two orders of magnitude lower electromagnetic field strength. As a consequence, the signal majorly stems from the interparticle locations. However, for applications of such dimers in TENOM or TERS, the

• optical response is primarily driven by the field at the end point of the probe. Theoretical investigations of the electromagnetic field distribution of these dimers at particular wavelengths demonstrate a tight connection of the optical response associated with the two particular locations, i.e., the gap

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

• molecules with different alkyl terminal groups. The absorption spectrum of the liquid crystals has two pronounced peaks at wavelengths of 265 nm and 314 nm. These are the bands of the monomers and dimers. Most probably, the band with a maximum of about 414 nm is associated to the excimer luminescence of the

• LC monomers and dimers [21]. The peak of the maximum luminescence intensity of QDs with 5 nm core diameter is at the wavelength of 630 nm. The quantum yield of the semiconductor NPs luminescence strongly depends on the polarity of the surrounding molecules, the electrostatic properties, the

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• nanogratings [15], plasmonic oligomers [16], dolmen arrangements of nanorods [17] and ring–disk dimers [18]. Fano resonances have also been observed in nanoholes such as coaxial apertures [19] and dolmen nanocavities [18]. The performance of an array of double split-ring cavities [20] as biosensors using Fano

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• star shape [17] typical for the rotational symmetry of its triangular lattice. More complex objects, such as dimers, reveal other spatial features, showing the bonding and antibonding states [18]. In a somewhat different context it has been pointed out [19] that exchange coupling between numerous

Induced smectic phase in binary mixtures of twist-bend nematogens

• Anamarija Knežević,
• Irena Dokli,
• Marin Sapunar,
• Suzana Šegota,
• Ute Baumeister and
• Andreja Lesac

Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122

• innovative applications. Even before this new nematic phase was described as a twist-bend nematic phase, the mixtures of LC compounds exhibiting it were prepared and investigated. The aim of those studies was to further explore this unknown nematic phase [4][5][6] or to confirm which new dimers exhibit this

• interactions, dipole-induced dipole interactions, and excluded volume effects [14][15]. In this study, we report on the unusual behaviour of a binary mixture between two twist-bend nematogens. Previously we reported on the mesomorphic behaviour of various imino-linked dimers that displayed both uniaxial

• nematic (N) and twist-bend nematic phases (NTB) [16][17]. Continuing our investigation on these systems, we performed a study on how mixing two imino-linked bent-shaped dimers with a rather large difference in molecular length affects their mesomorphic properties. For the purpose of this study, we

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• heads face each other, forming rows of RA dimers (Figure 2d – side view). In the other configuration (tail–head), the tail of one molecule interacts with the carbon ring head of another (Figure 2c – top view and Figure 2e – side view). Comparing the total energy involved in both tail–tail and tail–head

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• range observed in Au-PMe3 complexes summarized in Table 1 (2.233(3)–2.276(6) Å). Of major interest are the aurophilic interactions. Four out of the six molecules in the asymmetric unit form weakly bound dimers with rather long Au∙∙∙Au interactions of 3.3130(4) Å and 3.4073(5) Å (average: 3.33602(5) Å

• unit form weakly bound dimers with Au–Au interactions. In contrast, two molecules in the unit cell show Au–Au distances above 4.0 Å and should basically be considered monomeric. These monomerically bound MeAuPMe3 molecules have a lower desorption energy, allowing them to leave to the gas phase. Once

Alternating current magnetic susceptibility of a ferronematic

• Natália Tomašovičová,
• Jozef Kováč,
• Veronika Gdovinová,
• Nándor Éber,
• Tibor Tóth-Katona,
• Jan Jadżyn and
• Peter Kopčanský

Beilstein J. Nanotechnol. 2017, 8, 2515–2520, doi:10.3762/bjnano.8.251

• our phenomenological model: The higher concentration of MNPs results in a larger number of individual particles and dimers that contribute to the ac susceptibility. Nevertheless, the effect is not linear; multiparticle aggregates with nearly closed flux virtually do not contribute to χ′ and at the

• disaggregation capability, i.e., it produces a slightly larger number of single MNPs or dimers contributing to χ′(T), and some of them remain nonaggregated above the isotropic-to-nematic phase transition temperature. (vi.) In addition to the bias-field-dependent shift of the χ′(T) curve mentioned above, for Hdc

Ester formation at the liquid–solid interface

• Nguyen T. N. Ha,
• Thiruvancheril G. Gopakumar,
• Nguyen D. C. Yen,
• Carola Mende,
• Lars Smykalla,
• Maik Schlesinger,
• Roy Buschbeck,
• Tobias Rüffer,
• Heinrich Lang,
• Michael Mehring and
• Michael Hietschold

Beilstein J. Nanotechnol. 2017, 8, 2139–2150, doi:10.3762/bjnano.8.213

• govern the interaction between TMA molecues within the TMA dimer tapes [26][27]. The unit cell parameters of this LP are A ≈ 35 Å and B ≈ 10 Å. Within the unit cell, TMA dimers form an angle of α ≈ 8° with respect to the long side of the unit cell (A). The angle θ (≈ 84°) is the angle between the unit

• groups of undecanol and the hydrogen atoms of the C–H groups of TMA. A closer packing is only possible via reorganization of TMA dimers as seen in LP2 or via a gauche isomer of undecanol parallel to the surface. However, the undecanol molecules are observed as linear features in the STM images, which is

• of LP increases slightly as the time of sonication increases, whereas the other geometrical parameters (e.g., B, θ) remain nearly unchanged. As a result, the packing density of LP decreases slightly with increasing sonication time. It is to be noted that the distances between TMA dimers in the dimer

Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• arbitrary nearest-neighbor Coulomb interactions has recently been studied by two of us [15]. There, the molecules have been assumed to be symmetric, which would for example be appropriate for a CoPc layer. In the present work, we consider a minimal model for a layer of dimers such as F16CoPc/MnPc [11][12

Bi-layer sandwich film for antibacterial catheters

• Gerhard Franz,
• Florian Schamberger,
• Hamideh Heidari Zare,
• Sara Felicitas Bröskamp and
• Dieter Jocham

Beilstein J. Nanotechnol. 2017, 8, 1982–2001, doi:10.3762/bjnano.8.199

• layers with a high conformity, albeit at slow growth rates [39]. Growth rate as function of pressure The reactor spatially separates the regions of activation (cleavage of dimers) and polymerization (oligomers or polymers in the vapor vs deposition as surface reaction). The growth rate, GR, depends on

Non-intuitive clustering of 9,10-phenanthrenequinone on Au(111)

• Ryan D. Brown,
• Rebecca C. Quardokus,
• Natalie A. Wasio,
• Jacob P. Petersen,
• Angela M. Silski,
• Steven A. Corcelli and
• S. Alex Kandel

Beilstein J. Nanotechnol. 2017, 8, 1801–1807, doi:10.3762/bjnano.8.181

• . When comparing the two ordered features of this surface, it is useful to consider the only reported crystal structure of 9-fluorenone. The bulk crystal structure is comprised of 9-fluorenone dimers, slightly offset and oriented 180° apart so that the carbonyls face the hydrogen atoms at the 1- or 8

• -positions of the aromatic rings for each molecule [36]. This is very different from the binding motifs present in the polymorphs of 9,10-phenanthrenequinone, and the fact that this molecule can form dimers with this orientation might be the reason that tetramers do not form. There might be little to no

• than the linear rows by about 0.5 Å if this feature actually was comprised of 9-fluorenone dimers. Another bonding motif of 9-fluorenone is a catemer, in which each molecule binds to two other molecules in the structure, in a co-crystal with perfluoro-ortho-phenylmercury [37]. The orientation of the

(Metallo)porphyrins for potential materials science applications

• Lars Smykalla,
• Carola Mende,
• Michael Fronk,
• Pablo F. Siles,
• Michael Hietschold,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1786–1800, doi:10.3762/bjnano.8.180

• by especially the halogen substitution pattern of the monomer. Notably, probably the first example of halogen-based, two-dimensionally covalent self-assembly on a surface was demonstrated by Grill and co-workers [40], where they showed that dimers, oligomer chains and small 2D covalent networks could

Adsorption and diffusion characteristics of lithium on hydrogenated α- and β-silicene

• Fadil Iyikanat,
• Ali Kandemir,
• Cihan Bacaksiz and
• Hasan Sahin

Beilstein J. Nanotechnol. 2017, 8, 1742–1748, doi:10.3762/bjnano.8.175

• nearest silicene atoms of which are lower Si and upper Si atoms. In this hexagonal unit, Si–Si bond distances are 2.37 Å. In α-II, there are two lower-Si-dimers that are placed opposite to each other. Si–Si bond lengths of two Si dimers are 2.36 Å and 2.39 Å. The bond distances between upper Si and lower

• similar to that of α-I. However, compared to α-I, the distances between lower Si and upper Si atoms are not the same and they are 2.37 Å and 2.38 Å. β-II has two lower-Si-dimers which are placed opposite to each other. Si–Si bond lengths of both lower Si dimers are 2.35 Å. The bond distances between upper

• Si and lower Si atoms are 2.36 Å to 2.37 Å. β-III has two neighboring lower Si dimers. Three Si atoms in these two neighboring Si dimers are almost in the same plane with bond lengths of 2.35 Å and 2.37 Å. The bond distances between upper Si and lower Si atoms are 2.37 Å. Consequently, unlike the H-α

Three-in-one approach towards efficient organic dye-sensitized solar cells: aggregation suppression, panchromatic absorption and resonance energy transfer

• Jayita Patwari,
• Samim Sardar,
• Bo Liu,
• Peter Lemmens and
• Samir Kumar Pal

Beilstein J. Nanotechnol. 2017, 8, 1705–1713, doi:10.3762/bjnano.8.171

• anomaly is the much better light harvesting ability of the monomer of SQ2 compared to the aggregated dye. The photocurrent around 600 nm is harvested mainly by SQ2 dimers, but the aggregation promotes a lack of directionality of excited-state electrons of the dye. As a consequence the harvesting ability

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

• Florian Rückerl,
• Daniel Waas,
• Bernd Büchner,
• Martin Knupfer,
• Dietrich R. T. Zahn,
• Francisc Haidu,
• Torsten Hahn and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 1601–1615, doi:10.3762/bjnano.8.160

• bulk material consisting of MnPc/F16CoPc dimers could be prepared via the co-evaporation of these two materials. Spectroscopic studies of the resulting films confirmed the formation of MnPc/F16CoPc charge-transfer dimers in analogy to the related interface as discussed above [139]. The electronic

Stable Au–C bonds to the substrate for fullerene-based nanostructures

• Taras Chutora,
• Jesús Redondo,
• Bruno de la Torre,
• Martin Švec,
• Pavel Jelínek and
• Héctor Vázquez

Beilstein J. Nanotechnol. 2017, 8, 1073–1079, doi:10.3762/bjnano.8.109

• features to be dimers of molecules damaged during the sputtering. The number of observed dimers was very limited. We turn to the features on the herringbone corners. Given the higher reactivity of these elbow sites, we consider the possibility of the bright spots being normal C60 molecules and for the

• molecules attached to the herringbone elbow sites. Two dimers are enclosed by blue circles. Top and side views of the computed structure of C59 structural isomers. Carbon atoms around the vacancy are shown in red. (a) Initial structure for geometry optimization, obtained from a C60 molecule by removing one

Calculating free energies of organic molecules on insulating substrates

• Julian Gaberle,
• David Z. Gao and
• Alexander L. Shluger

Beilstein J. Nanotechnol. 2017, 8, 667–674, doi:10.3762/bjnano.8.71

• organic molecules on an insulating substrate are discussed. The adhesion of 1,3,5-tri(4'-cyano-[1,1'-biphenyl]-4-yl)benzene (TCB) and 1,4-bis(4-cyanophenyl)-2,5-bis(decyloxy)benzene (CDB) molecules to step edges on the KCl(001) surface and the formation of molecular dimers were studied using classical

• adsorption of these molecules at high temperatures [43]. Here we investigate free-energy profiles for the adhesion of these molecules to a monatomic step edge and the formation of dimers on a clean terrace. These processes are important during the early stages of self-assembly and a better understanding of

• dynamics simulations, another setup was tested: TCB molecules will readily form dimers on terraces, in which two molecules will align next to each other (see inset of Figure 5). This process occurs spontaneously in MD simulations at 300 K when two TCB molecules are placed near each other on a KCl terrace

Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces

• Ana C. S. Alcântara,
• Margarita Darder,
• Pilar Aranda and
• Eduardo Ruiz-Hitzky

Beilstein J. Nanotechnol. 2016, 7, 1772–1782, doi:10.3762/bjnano.7.170

• SDS-PAGE gel also shows bands around 50 kDa that reveal the presence of α-zein dimers [30][31], as well as bands at higher molecular mass (around 150 and 250 kDa) corresponding to other protein aggregates, such as trimers, tetramers and/or oligomers. Electrophoresis measurements conducted in the PCT

• and EXT phases revealed that the protein pattern of PCT (Figure 1B, lane c) is very similar to that of neat zein (Figure 1B, lane a), with bands of α-zein and its dimers at approximately 21–25 kDa and 50 kDa, respectively. An intense band set of protein aggregates is also observed between 150 kDa and

The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

• Yevgeniy R. Davletshin and
• J. Carl Kumaradas

Beilstein J. Nanotechnol. 2016, 7, 869–880, doi:10.3762/bjnano.7.79

• element method. The thresholds of optical breakdown for off- and on-resonance irradiated gold nanosphere monomers were compared against nanosphere dimers, trimers, and gold nanorods with the same overall size and aspect ratio. The optical breakdown thresholds had a stronger dependence on the optical near

• optical breakdown process [37][42][43]. Hatef and Meunier [43] recently reported the impact of size and inter-particle distance for femtosecond laser pulse widths on the energy absorption by gold nanosphere dimers and by the plasma surrounding the dimers. They showed that the energy deposition in the

• plasma increases with decreasing gap distance between dimers down to a 4 nm gap, which was the smallest gap they examined. Boulais et al. [37] revealed the existence of two different physical regimes of plasma generation in the vicinity of a gold nanorod during ultrafast pulse exposure. For a fluence

Rigid multipodal platforms for metal surfaces

• Michal Valášek,
• Marcin Lindner and
• Marcel Mayor

Beilstein J. Nanotechnol. 2016, 7, 374–405, doi:10.3762/bjnano.7.34