Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• approaches. The SBM is a two-dimensional approximation of the real system, so that effects due to the thickness of the layer are neglected. Specifically, any effect due to the vertical stress distribution cannot be captured. While these can be minimized in the case H << L, it is still useful to compare the

• , Dassault Systèmes, France) and employing C3D8I elements, which are 8-node bricks with 8 points of integration and incompatible modes. The choice of this element type allows a good representation of the stress singularities at the edges (see Supporting Information File 5). A convergence study is carried out

• time evolution obtained with FEM is also shown. In this case, the behaviour is strongly dependent on the thickness of the block. The time interval Δts needed to reach the static friction peak can be estimated starting from the shear stress τ = Gγ, where G is the shear modulus. If the shear deformation

Adhesive contact of rough brushes

• Qiang Li and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2018, 9, 2405–2412, doi:10.3762/bjnano.9.225

• of stress in the vicinity of the boundary of the “apparent contact”. In the present paper we extend the previous work by considering “rough brushes”. Related problems have been studied using a number of purely statistical models, which did not consider the elastic interactions between asperities

Hydrothermal-derived carbon as a stabilizing matrix for improved cycling performance of silicon-based anodes for lithium-ion full cells

• Mirco Ruttert,
• Florian Holtstiege,
• Jessica Hüsker,
• Markus Börner,
• Martin Winter and
• Tobias Placke

Beilstein J. Nanotechnol. 2018, 9, 2381–2395, doi:10.3762/bjnano.9.223

• changes of ≈300–400% during the lithiation/delithiation process [15][16][17]. The latter issue leads to severe mechanical stress and causes rupturing of the electrode, electronic contact loss between active material and current collector/conductive carbon network and pulverization. Furthermore, the

• ) that cannot be found on the surface of the electrode in Figure 5a and 5b, showing the C:Si 90:10 composite. It can be concluded that the mechanical stress caused by the volume expansion of the Si during the lithiation/delithiation process cannot be completely buffered by the amorphous carbon matrix and

• Si-NPs sufficiently. This resulted in mechanical stress and the formation of cracks within the electrodes, as well as continuous SEI formation. Despite the fact that the initial Coulombic efficiency of the synthesized materials was quite low, we could show that these materials are applicable as anode

Pinning of a ferroelectric Bloch wall at a paraelectric layer

• Vilgelmina Stepkova and
• Jiří Hlinka

Beilstein J. Nanotechnol. 2018, 9, 2356–2360, doi:10.3762/bjnano.9.220

• comparison, Figure 4 shows the profile of the Ising domain wall, which is obtained by the same simulation but under an epitaxial compressive stress of 3.0 GPa, applied in the plane perpendicular to the spontaneous polarization as described in [11]. The polarization profile relaxed within the SrTiO3

• needed to drive BaTiO3 into the rhombohedral ferroelectric phase). Phase-field simulations for pure BaTiO3 single crystal and for the BaTiO3–SrTiO3 crystalline superlattice at stress-free mechanical conditions were performed using the phase-field simulation code ferrodo [8]. The approximate profile of

• panel. Relaxed profile of the polarization components across 180-degree ferroelectric wall in rhombohedral BaTiO3. Relaxed profile of the polarization components across 180-degree ferroelectric wall in rhombohedral BaTiO3 under epitaxial compressive stress of 3 GPa. Relaxed profile of the polarization

Nanoscale characterization of the temporary adhesive of the sea urchin Paracentrotus lividus

• Ana S. Viana and
• Romana Santos

Beilstein J. Nanotechnol. 2018, 9, 2277–2286, doi:10.3762/bjnano.9.212

• groove typically found on the surface of amyloid fibrils. Therefore, besides binding to amyloid proteins and peptides, thioflavin-T can also bind DNA, some polysaccharides and β-sheet-rich proteins [25]. Taken together, our results stress the importance of probing marine adhesives under native conditions

Surface energy of nanoparticles – influence of particle size and structure

• Dieter Vollath,
• Franz Dieter Fischer and
• David Holec

Beilstein J. Nanotechnol. 2018, 9, 2265–2276, doi:10.3762/bjnano.9.211

• Gibbs using the term “surface tension” [1][2]. In the meantime, it has become clear that in case of solids one has to distinguish between “surface energy” and “surface stress”. Both quantities are related by the Shuttleworth equation [3]. Since the surface stress, σ, exerts a pressure, p, on a curved

• into a term depending on the binding in the solid (“chemical contribution”), γbond, and into a minor term caused by the stress state due to the surface stress (“mechanical contribution”), γmech, as The contribution of the mechanical energy to the surface energy is, compared to the chemical contribution

• , minor [3]. Based on this clarification, it is obvious that the lattice contraction data for small particles, abundant in the literature, may be used to calculate the size dependent surface stress, (see, e.g., [6][7][8]) but not, as it is done sometimes [9][10], to calculate the surface energy (“surface

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

• compressive or dilating stress is expected to switch the HP conductivity from p- to n-type and vary the bandgap within a range of 1.35–2.50 eV [142]. Typically, Ge HPs are prone to hydrolytic decomposition when coming in contact with a humid environment [144]. Possible mechanisms and pathways of the

Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers

• Deepika Jhajhria,
• Dinesh K. Pandya and
• Sujeet Chaudhary

Beilstein J. Nanotechnol. 2018, 9, 2198–2208, doi:10.3762/bjnano.9.206

• function of the angle θ. The two-fold symmetry for all samples clearly indicates the existence of the uniaxial magnetic anisotropy (UMA). This UMA results from the breakdown of the azimuthal symmetry in the deposited films, which is likely to be caused by the anisotropic stress in the films generated due

• to the oblique deposition geometry [39]. Since CoFeB is highly sensitive to this induced anisotropic stress (owing to their large positive saturation magnetostriction coefficient λs [40]), the deposition geometry effectively results in the observed UMA [41]. The UMA in films is found to be directly

High-throughput synthesis of modified Fresnel zone plate arrays via ion beam lithography

• Kahraman Keskinbora,
• Umut Tunca Sanli,
• Margarita Baluktsian,
• Corinne Grévent,
• Markus Weigand and
• Gisela Schütz

Beilstein J. Nanotechnol. 2018, 9, 2049–2056, doi:10.3762/bjnano.9.194

• defects. Only in three of the FZPs minor defects in a few zones were observed, which is expected to reduce the DE slightly but does not hinder the function of the optic overall. The flaws were attributed to the local variations in the film structure and stress. The majority of the FZPs was intact and

Fabrication of photothermally active poly(vinyl alcohol) films with gold nanostars for antibacterial applications

• Mykola Borzenkov,
• Maria Moros,
• Claudia Tortiglione,
• Serena Bertoldi,
• Nicola Contessi,
• Silvia Faré,
• Angelo Taglietti,
• Agnese D’Agostino,
• Piersandro Pallavicini,
• Maddalena Collini and
• Giuseppe Chirico

Beilstein J. Nanotechnol. 2018, 9, 2040–2048, doi:10.3762/bjnano.9.193

• -bearing carboxylic groups.The representative stress–strain curves of the fabricated films are shown in Figure 3. The detailed information about the set-up and data analysis is provided in the Experimental section. The mechanical parameters obtained by the stress–strain curves are reported in Table 1. The

• stress–strain curves of the three types of films followed the same trend, however being characterized by different elastic modulus, maximum stress and maximum strain values. In particular, PVA films without GNSs showed the lowest stiffness value in comparison with both types of PVA-GNS films (p < 0.05

• ). At the same time films prepared with GNSs coated with SH-PEG−COOH were characterized by the highest value of maximum stress when compared to films prepared with GNSs coated with SH-PEG–OCH3 and with bare PVA films (p < 0.05). All the compositions showed instead similar values of the maximum strain

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• friction was recently observed for micro- and macroscale systems based on incommensurate sliding between graphene-covered spheres or “nanoscrolls” and substrates [76][77]. Also a decrease of friction shear stress with increasing number of layers has been observed for graphene over Si/SiO2 in vacuum

• , only small particles adhere to the sublinear superlubric scaling law, while larger particles show a linear scaling between friction and area, equivalent to a constant shear stress [100]. This can be explained by an enhanced interaction between the Sb atoms and the substrate, as was found by ab initio

Self-assembled quasi-hexagonal arrays of gold nanoparticles with small gaps for surface-enhanced Raman spectroscopy

• Emre Gürdal,
• Simon Dickreuter,
• Fatima Noureddine,
• Pascal Bieschke,
• Dieter P. Kern and
• Monika Fleischer

Beilstein J. Nanotechnol. 2018, 9, 1977–1985, doi:10.3762/bjnano.9.188

• gold film we obtain a lower limit of the enhancement factor of ≈300. This is a very conservative lower limit, and compared to values commonly reported in literature it is significantly smaller, but we would like to stress that the estimation of SERS enhancement factors is inherently difficult and is

Nonlinear effect of carrier drift on the performance of an n-type ZnO nanowire nanogenerator by coupling piezoelectric effect and semiconduction

• Yuxing Liang,
• Shuaiqi Fan,
• Xuedong Chen and
• Yuantai Hu

Beilstein J. Nanotechnol. 2018, 9, 1917–1925, doi:10.3762/bjnano.9.183

• being negatively charged. At the same time, a Schottky barrier formed between the AFM tip and the nanowire and the piezoelectric potential will not disappear as long as the mechanical stress is maintained. This potential can be made use of to generate an electrical current [30]. Recently, Fan et al

The role of the Ge mole fraction in improving the performance of a nanoscale junctionless tunneling FET: concept and scaling capability

• Hichem Ferhati,
• Fayçal Djeffal and
• Toufik Bentrcia

Beilstein J. Nanotechnol. 2018, 9, 1856–1862, doi:10.3762/bjnano.9.177

• applications. Moreover, this study can be extended by investigating the impact of other parameters such as the interfacial defects between both Si and SiGe materials and the degradation-related ageing effects including stress. To do so, new complex models and numerical simulations need to be developed

Numerical analysis of single-point spectroscopy curves used in photo-carrier dynamics measurements by Kelvin probe force microscopy under frequency-modulated excitation

• Pablo A. Fernández Garrillo,
• Benjamin Grévin and
• Łukasz Borowik

Beilstein J. Nanotechnol. 2018, 9, 1834–1843, doi:10.3762/bjnano.9.175

• -state condition is reached after a certain number of excitation pulses (charge equilibrium). In Figure 6 we note that as expected, the higher the modulation frequency is the more illumination cycles are needed to attain the charge-equilibrium state. Nonetheless, we stress that even though more cycles

• dynamics are governing the SPV behavior of the sample, as it is the case for instance for OPV samples exhibiting a high density of low-energy states (traps). Nonetheless, we stress that even if the calculated photo-carrier lifetime values do not fully agree with those reported in [4], the ratio between the

Multimodal noncontact atomic force microscopy and Kelvin probe force microscopy investigations of organolead tribromide perovskite single crystals

• Yann Almadori,
• David Moerman,
• Jaume Llacer Martinez,
• Philippe Leclère and
• Benjamin Grévin

Beilstein J. Nanotechnol. 2018, 9, 1695–1704, doi:10.3762/bjnano.9.161

• first approximation inversely proportional to the illumination intensity) remains a hidden parameter that cannot be directly deduced from our data (contrary to conventional macroscopic measurements where transient photovoltage can be combined with charge extraction [37]). Here, we stress that the

Nanoscale electrochemical response of lithium-ion cathodes: a combined study using C-AFM and SIMS

• Jonathan Op de Beeck,
• Nouha Labyedh,
• Alfonso Sepúlveda,
• Valentina Spampinato,
• Alexis Franquet,
• Thierry Conard,
• Philippe M. Vereecken,
• Wilfried Vandervorst and
• Umberto Celano

Beilstein J. Nanotechnol. 2018, 9, 1623–1628, doi:10.3762/bjnano.9.154

• hybrid metrology approach combining SPM with SIMS, this is a technique able to observe the actual Li concentration. Using the C-AFM tip as a nanoscaled electrode, we can now stress films at different bias values by scanning over the surface (8.5 min) and subsequently observe the induced conductivity

• for its pristine state (Figure 1b). The different conductivity changes between MnO2 and LMO can be attributed to the presence of lithium in LMO as this can migrate and locally accumulate at the surface driven by the applied electric field. The impact of the 10 V stress is described later in the text

• , as it involves a dedicated interpretation due to the relatively high voltage involved. A more quantitative comparison of the regions is shown in Figure S1 (Supporting Information File 1). The line graph indicates clearly the increasing conductivity change (69%, 160%) with increasing stress (3 V, 5 V

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate

• Aiden A. Martin and
• Philip J. Depond

Beilstein J. Nanotechnol. 2018, 9, 1282–1287, doi:10.3762/bjnano.9.120

• instabilities produced during the thermally induced fabrication process. Exposure to high temperatures is incompatible with many substrate materials and leads to the development of undesirable stress, which often results in film cracking and delamination [1]. A rapidly developing technique that has been

The electrical conductivity of CNT/graphene composites: a new method for accelerating transmission function calculations

• Olga E. Glukhova and
• Dmitriy S. Shmygin

Beilstein J. Nanotechnol. 2018, 9, 1254–1262, doi:10.3762/bjnano.9.117

• single-walled carbon nanotubes (SWCNTs). One of the advantages of this material is its high strength and resistance to mechanical stress [2][3][4]. In combination with high electrical capacity and efficient electronic transfer between graphene sheets, this nanomaterial has already been recognized as

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• strain (Figure S1, Supporting Information File 1). The band gap variation depends on the viewing direction along the lattice. In the laboratory, an external strain can be imparted by different means such as adlayer–substrate lattice mismatch, external loading, bending or by applying stress on the

Atomistic modeling of tribological properties of Pd and Al nanoparticles on a graphene surface

• Alexei Khomenko,
• Miroslav Zakharov,
• Denis Boyko and
• Bo N. J. Persson

Beilstein J. Nanotechnol. 2018, 9, 1239–1246, doi:10.3762/bjnano.9.115

• different temperatures, and showed how the static friction and contact stiffness depend on the contact area. They observed “contact aging” due to stress-aided, thermally activated atomic rearrangement processes. The term “contact aging” [6] is related to time-dependent atomic reconstructions at the

• . Figure 5 depicts the frictional shear stress τ as a function of the contact area. The average shear stress is τ ≈ 9.9 MPa for the Al particles and 12.2 MPa for Pd particles. The values of shear stress in experiments (Figure 2 in [7]) for Sb particles on MoS2 substrate varies from 1 MPa to 3 MPa with

• contact area changes from 1000 nm2 to 100000 nm2. Also, for Sb particles on highly oriented pyrolytic graphite τ is in the range from 0.1 MPa to 1 MPa with the same changes of contact area. In [7] the shear stress decreases linearly with contact area while we find that τ is nearly independent of it. This

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• achieve a combined signal of sufficient intensity. Alternatively, techniques such as those developed for single plasmonic nanoparticle sensing [28] might be applied to an isolated chiral Majorana device. Particularly, among the latter we stress the techniques for single-particle absorption that have

Imaging of viscoelastic soft matter with small indentation using higher eigenmodes in single-eigenmode amplitude-modulation atomic force microscopy

• Miead Nikfarjam,
• Enrique A. López-Guerra,
• Santiago D. Solares and
• Babak Eslami

Beilstein J. Nanotechnol. 2018, 9, 1116–1122, doi:10.3762/bjnano.9.103

• indentation for a fixed value of the oscillation amplitude A0, due to their higher force constant. An implicit qualitative conclusion is that similar sensitivity should be observed during single-eigenmode AM-AFM for different eigenmodes, i and j, when kiAi = kjAj. Again, it is important to stress that this

• the deformation-rate-dependence of viscoelastic materials. We encourage further research in this area, especially in liquids, where the softest (biological) samples find their native environment. Generalized Maxwell or Wiechert mechanical model diagram representing the relationship between stress and

• Laplace transformed stress is regarded as the excitation and the transformed strain as the response. Numerical simulations corresponding to a parabolic AFM tip tapping on a polyisobutylene surface, described as a viscoelastic material containing multiple characteristic times using the generalized Maxwell

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

• reactions associated with NPs and NSMs and the regulations implemented by different countries to reduce the associated risks are also discussed. Keywords: nanomaterial classification; nanomaterial history; nanotoxicity; oxidative stress; reactive oxygen species; regulations; Review Introduction

• cells can cause granulomatous reactions, oxidative stress and inflammation, leading to fibroplasia and neoplasia in lungs. The results also suggested that humans are routinely exposed to carbon nanotubes and showed that the outcome is similar to the vehicle exhaust samples collected in Paris, ambient

An implementation of spin–orbit coupling for band structure calculations with Gaussian basis sets: Two-dimensional topological crystals of Sb and Bi

• Sahar Pakdel,
• Mahdi Pourfath and
• J. J. Palacios

Beilstein J. Nanotechnol. 2018, 9, 1015–1023, doi:10.3762/bjnano.9.94

• any further here. Finally, we stress that our proposed implementation is not restricted to any specific Gaussian-type basis set. As an advantage when compared to, e.g., TB calculations, it can capture the SOC effect for more flexible and larger basis sets when a minimal basis does not give