Morphology of SiO₂ films as a key factor in alignment of liquid crystals with negative dielectric anisotropy

• Volodymyr Tkachenko,
• Antigone Marino,
• Eva Otón,
• Noureddine Bennis and
• Josè Manuel Otón

Beilstein J. Nanotechnol. 2016, 7, 1743–1748, doi:10.3762/bjnano.7.167

• technique as a reference for such materials. The measure of the optical constants [21], tilt distribution and anchoring strength [22] in nematic LC cells is well reported. The integration of VASE with other techniques [23] has also been investigated to improve the reliability and accuracy of the optical

• < 75° high discrepancy is observed between the data of different authors, as a transition occurs from "pebble dash-like" structures to columnar structure of SiO2 film [2]. We believe that LC anchoring becomes spatially inhomogeneous, unstable and sensitive to the small changes of film deposition

Analysis of self-heating of thermally assisted spin-transfer torque magnetic random access memory

• Austin Deschenes,
• Sadid Muneer,
• Mustafa Akbulut,
• Ali Gokirmak and
• Helena Silva

Beilstein J. Nanotechnol. 2016, 7, 1676–1683, doi:10.3762/bjnano.7.160

• tunneling junction. We compare self-heating for different common passivation materials, positive and negative electrical current polarity, and different device thermal anchoring and boundaries resistance configurations. The variations considered are found to result in significant differences in maximum

• temperatures reached. Average increases of 3 K, 10 K, and 100 K for different passivation materials, positive and negative polarity, and different thermal anchoring configurations, respectively, are observed. The highest temperatures, up to 424 K, are obtained for silicon dioxide as the passivation material

• , positive polarity, and low thermal anchoring with thermal boundary resistance configurations. Interestingly it is also found that due to the tunneling heat, Peltier effect, device geometry, and numerous interfacial layers around the magnetic tunnel junction (MTJ), most of the heat is dissipated on the

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• deposition, or the necessity of some surface pre-treatment), (2) the structure of the deposited molecule (e.g., specific anchoring groups), and (3) a particular balance of the molecule–molecule and molecule–substrate interactions (e.g., different faces of the same bulk material may have distinct properties

• upright as the coverage increases – an effect observed on both (110) and (011) surfaces [55][56]. Let us first review the results for zinc protoporphyrin (ZnPP) adsorbed on a rutile TiO2(110) surface [55]. To chemically anchoring the molecule to the oxide surface, it is important to consider that

Nano- and microstructured materials for in vitro studies of the physiology of vascular cells

• Alexandra M. Greiner,
• Adria Sales,
• Hao Chen,
• Sarah A. Biela,
• Dieter Kaufmann and
• Ralf Kemkemer

Beilstein J. Nanotechnol. 2016, 7, 1620–1641, doi:10.3762/bjnano.7.155

• (i.e., focal adhesions (FAs) that are complexes of proteins anchoring to the substrate and regulating cell adhesion strength, and actin cytoskeleton) have been observed to change and adapt to surface topography. Probably the influence of the topography on these internal structures provokes the

Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• vivo studies. It is not clear whether the polyether chains of the poloxamer Pluronic® served as a non-ionic wrapping agent securing solid anchoring of the MWCNTs on the cell membrane [23][24]. Alternatively, its role might be more focused on stabilizing a disperse system by preventing the CNTs from

• functionalization of oMWCNT is aimed at introducing specific organic ligands to permanently chelate metal ions or their oxides. This is the manner in which Lamanna prepared an oligoglycol dendron with phosphonic groups responsible for SPIO anchoring. The ligand was introduced on the alkyne-derived oMWCNT by a click

• . Magnetic hysteresis loops close to zero magnetization in a varied magnetic field is typical behavior proving the super- [34][43] or paramagnetic [22] character of the introduced nanoparticles. Initially, the separately produced SPIOs, such as SPIO@Lac-Gly, exhibit higher magnetization, but their anchoring

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• electronic structure of the C K-edge in the nanocomposites was probed by electron energy loss spectroscopy, highlighting the key role of the MWCNT growth defects in anchoring HfO2 NPs. A combined optical emission and absorption spectroscopy approach illustrated that, in contrast to HfO2 NPs, the metallic

• explanation to this selective anchoring is provided below and also in the EELS section. In Figure 1c, a HAADF-HRSTEM image exhibits small agglomerates of these nanoparticles on the MWCNT, where the diameter of the MWCNT has reduced due to buckling. The nanoparticles remain crystalline as displayed by the

• facilitate the decoration of these nanoparticles to the MWCNT. This mechanism of anchoring to the sidewalls is further probed in the EELS section. On the other hand, the side walls of the MWCNT do not appear to be atomically flat, and the outermost walls are not distinct, indicating damage to the walls of

Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

• Amanda García-García,
• Ricardo Vergaz,
• José F. Algorri,
• Gianluigi Zito,
• Teresa Cacace,
• Antigone Marino,
• José M. Otón and
• Morten A. Geday

Beilstein J. Nanotechnol. 2016, 7, 825–833, doi:10.3762/bjnano.7.74

• orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules. Keywords: Anchoring; carbon nanotubes; impedance; liquid crystal; negative anisotropy; Raman spectroscopy; reorientation; single-wall CNTs

• in thin cells is dictated by the anchoring forces of the conditioned surfaces. However, the orientation may be altered if an external (electric) field above a certain threshold voltage (Vth) is applied. As a result, the effective permittivity of the LC material varies with the applied voltage. The LC

• director reorients to minimize the system energy; this energy depends on the anchoring forces of the substrate, the elastic parameters of the LC, and the applied field [6]. Calamitic LCs – the most commonly used LC in all kinds of applications – are rod-like uniaxial molecules having different properties

Gold nanoparticles covalently assembled onto vesicle structures as possible biosensing platform

• M. Fátima Barroso,
• M. Alejandra Luna,
• Juan S. Flores Tabares,
• Cristina Delerue-Matos,
• N. Mariano Correa,
• Fernando Moyano and
• Patricia G. Molina

Beilstein J. Nanotechnol. 2016, 7, 655–663, doi:10.3762/bjnano.7.58

• and the polydispersity index of the SH–DOPC LUVs since these values are within the experimental error. Optimization of the SH/DOPC ratio for electrochemical measurements Different SH/DOPC ratios in the formation of vesicles were explored in order to find the optimal conditions for anchoring the AuNPs

• anchoring of the antibodies in futures studies because a certain spacing of the AuNPs is required for its proper orientation [25]. Figure 7c shows a TEM image of the LUVs decorated with AuNPs formed after 13 min of irradiation. The morphology of the AuNPs anchored on the vesicles shows hollow, nearly

Novel roles for well-known players: from tobacco mosaic virus pests to enzymatically active assemblies

• Claudia Koch,
• Fabian J. Eber,
• Carlos Azucena,
• Alexander Förste,
• Stefan Walheim,
• Thomas Schimmel,
• Alexander M. Bittner,
• Holger Jeske,
• Hartmut Gliemann,
• Sabine Eiben,
• Fania C. Geiger and
• Christina Wege

Beilstein J. Nanotechnol. 2016, 7, 613–629, doi:10.3762/bjnano.7.54

• cells is relatively low [55]. Hence ectopically produced TMV templates are not yet accessible. Finally, an attachment of functional molecules to virus surfaces equipped too densely with anchoring tags may also be inefficient. For these reasons, previous work on elongated viral enzyme carriers succeeded

Invariance of molecular charge transport upon changes of extended molecule size and several related issues

• Ioan Bâldea

Beilstein J. Nanotechnol. 2016, 7, 418–431, doi:10.3762/bjnano.7.37

• particularly true in (chemisorption) cases where the anchoring groups form covalent bonds to the electrodes. Within current approaches to molecular charge transport, mostly based on nonequilibrium Keldysh Green’s functions (NEGF) combined with density functional theory (DFT), the molecular device is

• , which quantify the hopping between the left and right molecular ends (“anchoring groups”, denoted by labels 1 and N, respectively) and the adjacent electrode ends (labels l = 1 and r = 1 for left and right electrodes in Equation 9). In Equation 9, the small molecule, which needs not to be one

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

• anchoring units in order to control the spatial arrangement of the protruding molecular subunit. Another interesting feature is the lateral orientation of these foot structures which, depending on the particular application, is equally important as the spatial arrangement of the molecules. The numerous

• approaches towards assembling and organizing functional molecules into specific architectures on metal substrates are reviewed here. Particular attention is paid to variations of both, the core structures and the anchoring groups. Furthermore, the analytical methods enabling the investigation of individual

• molecules as well as monomolecular layers of ordered platform structures are summarized. The presented multipodal platforms bearing several anchoring groups form considerably more stable molecule–metal contacts than corresponding monopodal analogues and exhibit an enlarged separation of the functional

Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures

• Tuan Anh Pham,
• Andreas Schreiber,
• Elena V. Sturm (née Rosseeva),
• Stefan Schiller and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2016, 7, 351–363, doi:10.3762/bjnano.7.32

• inorganic material. Here, we use hemolysin coregulated protein 1 (Hcp1) from Pseudomonas aeruginosa as a building and gluing unit for the formation of biohybrid structures by implementing cysteine anchoring points at defined positions on the protein rim (Hcp1_cys3). We successfully apply the Hcp1_cys3

Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes

• Yongfeng Tong,
• Tingming Jiang,
• Azzedine Bendounan,
• Makri Nimbegondi Kotresh Harish,
• Angelo Giglia,
• Stefan Kubsky,
• Fausto Sirotti,
• Luca Pasquali,
• Srinivasan Sampath and
• Vladimir A. Esaulov

Beilstein J. Nanotechnol. 2016, 7, 263–277, doi:10.3762/bjnano.7.24

• various applications such as catalysis, sensor development, hydrogen storage, thin films, and molecular electronics has focused on the study of self-assembled monolayers (SAMs) with different combinations of molecular architecture, and in particular, different molecule anchoring head groups. The latter

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

• with procedure B. The larger amount of GO obtained with procedure B (see Table 2) is therefore strictly related to the smaller fraction of bare silicon oxide surface exposed. In both cases GO adsorbs through interactions with the silver surface anchoring exclusively to the outer face of the nanocube

• nm for both procedures. Such high thickness values are in accordance with the formation of folded geometries of single GO sheets after anchoring to the nanoparticle surface. Nevertheless, AFM measurements reveal a smaller thickness compared to QCM for the same samples. This was expected since QCM

High electronic couplings of single mesitylene molecular junctions

• Yuki Komoto,
• Shintaro Fujii,
• Tomoaki Nishino and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2015, 6, 2431–2437, doi:10.3762/bjnano.6.251

• electronics. To bind a single molecule to metal electrodes, anchoring groups such as –SH [14] and –NH2 or (R)3–N [15][16] have been used. Such anchoring groups form strong chemical bonds with metal electrodes and the anchoring regions act as resistive space, leading to low electronic conductances of the

• single molecular junctions. Recently several groups [17][18][19][20] including ours [17][21][22] developed a direct π-binding technique, where a π-conjugated molecule is directly bound to metal electrodes without anchoring groups. The direct π-binding technique has been applied for various systems such

• experimentally obtained I–V characteristics to the Breit-Wigner model, the metal–molecule coupling Γ, and energy difference between Fermi level and conduction orbital ε0 are obtained. This I–V analysis has been applied for molecular junctions with a variety of anchoring groups. For example Γ = 60 meV and ε0

Nanostructured surfaces by supramolecular self-assembly of linear oligosilsesquioxanes with biocompatible side groups

• Maria Nowacka,
• Anna Kowalewska and
• Tomasz Makowski

Beilstein J. Nanotechnol. 2015, 6, 2377–2387, doi:10.3762/bjnano.6.244

• LPSQ-COOH/X allow for a very efficient polymer anchoring on the surface due to both multipoint ionic substrate–adsorbate interactions and adsorbate–adsorbate hydrogen bonding [37]. The formation of ordered SAMs and PSAMs at the liquid–solid interface can occur only if it is energetically allowed by

Orthogonal chemical functionalization of patterned gold on silica surfaces

• Francisco Palazon,
• Didier Léonard,
• Thierry Le Mogne,
• Francesca Zuttion,
• Céline Chevalier,
• Magali Phaner-Goutorbe,
• Éliane Souteyrand,
• Yann Chevolot and
• Jean-Pierre Cloarec

Beilstein J. Nanotechnol. 2015, 6, 2272–2277, doi:10.3762/bjnano.6.233

• immobilize proteins onto gold nanostructures on a silica substrate, as demonstrated by atomic force microscopy (AFM). These results are especially promising in the development of future biosensors where the selective anchoring of target molecules onto nanostructured transducers (e.g., nanoplasmonic

• hot spot areas. Orthogonal surface chemical functionalization appears to enable such directed anchoring of target biomolecules (Figure 1) [6][8][9]. Despite the aforementioned publications, there is still much to be investigated regarding the orthogonal functionalization of patterned metal on

Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring

• Yuya Kitaguchi,
• Satoru Habuka,
• Hiroshi Okuyama,
• Shinichiro Hatta,
• Tetsuya Aruga,
• Thomas Frederiksen,
• Magnus Paulsson and
• Hiromu Ueba

Beilstein J. Nanotechnol. 2015, 6, 2088–2095, doi:10.3762/bjnano.6.213

• cleavage of the junction by tip retraction (Figure 1b) provides a well-defined measure of the direct current through the molecule. To investigate the influence of the anchoring group on the conductance, we also prepared PhS on the surface. This molecule is imaged as a protrusion with a tail which is

• retraction were recorded. The height of the plateau, corresponding to the conductance for each molecule, is robust between repeated measurements and is larger by a factor of ≈2 for PhS. This demonstrates that the conductance is modified by chemical substitution of the anchoring atom from oxygen to sulfur. To

• . The role of the anchoring group (O vs S) on the junction geometry was also computed. Figure 5 compares the total energy differences and molecular tilt angles for PhO [12] and PhS junctions in flat and tilted configurations. While the energy difference is rather similar, the tilt angle is generally

Electrospray deposition of organic molecules on bulk insulator surfaces

• Antoine Hinaut,
• Rémy Pawlak,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2015, 6, 1927–1934, doi:10.3762/bjnano.6.195

• molecules which are more suitable for future devices and could incorporate additional functions and anchoring groups. In this work we present the adaptation of a UHV-ESI system to deposit triply fused porphyrin molecules on a bulk insulator KBr(001) sample and the analysis of theses deposits by high

• characterized theses islands showing molecular assemblies stabilized by π–π stacking organization and anchoring through the cyano group of the molecules and K+ ions of the surface. To achieve single molecule deposition, we added a pumping chamber in the setup that lowered the number of molecules reaching the

Conductance through single biphenyl molecules: symmetric and asymmetric coupling to electrodes

• Karthiga Kanthasamy and
• Herbert Pfnür

Beilstein J. Nanotechnol. 2015, 6, 1690–1697, doi:10.3762/bjnano.6.171

• groups like amine, nitro, nitrile, carboxy, iso cyanate, pyridine. The electron donating group leads to higher conductance while electron withdrawing groups have a smaller conductance. The Au–S thiol is a well known anchoring group due strong covalent bond coupling [15]. The iso cyano group has been

Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

• Riccardo Frisenda,
• Simge Tarkuç,
• Elena Galán,
• Mickael L. Perrin,
• Rienk Eelkema,
• Ferdinand C. Grozema and
• Herre S. J. van der Zant

Beilstein J. Nanotechnol. 2015, 6, 1558–1567, doi:10.3762/bjnano.6.159

• mechanically controlled break junction (MCBJ) technique. The four molecules studied share the same core structure, namely oligo(phenylene ethynylene) (OPE3), while having different aurophilic anchoring groups: thiol (SAc), methyl sulfide (SMe), pyridyl (Py) and amine (NH2). The focus of this paper is on the

• combined characterization of the electrical and mechanical properties determined by the anchoring groups. From conductance histograms we find that thiol anchored molecules provide the highest conductance; a single-level model fit to current–voltage characteristics suggests that SAc groups exhibit a higher

• theory combined with non-equlibrium Green’s function calculations help in elucidating the experimental findings. Keywords: anchoring groups; coherent transport; current–voltage; molecular electronics; single molecule; Introduction Molecular-scale electronics is a field that in recent years experienced

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• electrons, and therefore provide the anchoring points with a certain degree of flexibility allowing for the movement of the Ru4POM molecules. Additionally, a continuous deformation of the molecular structure is noticed throughout the imaging. A typical example is demonstrated in Figure 8c–i. The acquired

Enhanced fullerene–Au(111) coupling in (2√3 × 2√3)R30° superstructures with intermolecular interactions

• Michael Paßens,
• Rainer Waser and
• Silvia Karthäuser

Beilstein J. Nanotechnol. 2015, 6, 1421–1431, doi:10.3762/bjnano.6.147

• extensively studied self-assembled systems due to their rich structural and electronic properties [1]. A considerable interest in C60 films arises from their use in photovoltaic cells [2][3] and potential applications in molecular electronics [4]. Likewise, C60 molecules can be used as chemical anchoring

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

• Deborah Vidick,
• Xiaoxing Ke,
• Michel Devillers,
• Claude Poleunis,
• Arnaud Delcorte,
• Pietro Moggi,
• Gustaaf Van Tendeloo and
• Sophie Hermans

Beilstein J. Nanotechnol. 2015, 6, 1287–1297, doi:10.3762/bjnano.6.133

• Scienze 17/A, 43124 Parma, Italy 10.3762/bjnano.6.133 Abstract Heterometal clusters containing Ru and Au, Co and/or Pt are anchored onto carbon nanotubes and nanofibers functionalized with chelating phosphine groups. The cluster anchoring yield is related to the amount of phosphine groups available on

• nanocarbon surface. In the case of Ru–Pt species, anchoring occurs without reorganization through a ligand exchange mechanism. After thermal treatment, ultrasmall (1–3 nm) bimetal Ru–Pt nanoparticles are formed on the surface of the nanocarbons. Characterization by high resolution transmission electron

• the presence of additives, binders, etc. Results and Discussion Cluster anchoring Phosphine-functionalized carbon nanofibers and nanotubes were prepared in several steps, as previously reported [38] and shown in Figure 1. We have also successfully applied this methodology to ordered mesoporous carbon

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• molecules within the LB film do not strongly influence the molecule conductance. The results presented here complement earlier studies of single molecule conductance of 1 using STM-BJ methods, and support the growing evidence that the pyridyl group is an efficient and effective anchoring group in sandwiched

• molecular electronics have focused attention on this potential linker group as an alternative to solve these problems [87]. Previous studies of pyridyl-functionalized molecules in single molecule conductance studies [19][21][88][89][90][91] have revealed that this moiety can work as an anchoring group

• other LB films), the conductance value for compound 1 is 3–20 times greater than for LB films of other oligo(phenylene-ethynylene) (OPE) derivatives bearing anchoring groups such as thiol (–SH), amine (–NH2), carboxylate (–COO−), trimethylsilylethynyl (–C≡CSiMe3) or acetylide (–C≡C) [23][24][30][45