Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• properties of the substrate, we refrain from a definite assignment. In any case, our data clearly shows that the HOMO is at or within the conduction band of MoS2. By comparison with simulations, we thus arrive at a clear identification of the energy level alignment. Most notably, we find that the LUMO

• excited state allowed us to resolve vibronic states of the transiently negatively charged TCNQ molecule albeit only up to approx. 200 meV above the LUMO resonance, where contributions of MoS2 bands at Γ become strong. Our simulations reproduce the experimental satellite structure of the LUMO very well

A new photodetector structure based on graphene nanomeshes: an ab initio study

• Babak Sakkaki,
• Hassan Rasooli Saghai,
• Ghafar Darvish and
• Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

• , and then proceed with the design of the photodetector based on a suitable material. We further calculate the transport and photocurrent of the devices. To demonstrate improved performance of the proposed devices, we perform simulations on three types of devices. Graphene, GNMs and GNRs are materials

• simulations. We assumed a finite GNM length between the two contacts. The channel of the photodetector has three GNM supercells along the transport direction (X direction), while in the perpendicular direction the channel length is defined to be infinite. To compare the designed devices with other

Three-dimensional solvation structure of ethanol on carbonate minerals

• Hagen Söngen,
• Ygor Morais Jaques,
• Peter Spijker,
• Christoph Marutschke,
• Stefanie Klassen,
• Ilka Hermes,
• Ralf Bechstein,
• Lidija Zivanovic,
• John Tracey,
• Adam S. Foster and
• Angelika Kühnle

Beilstein J. Nanotechnol. 2020, 11, 891–898, doi:10.3762/bjnano.11.74

• molecular dynamics (MD) simulations. Within a single AFM data set we are able to resolve both the first laterally ordered solvation layer of ethanol on the calcite surface as well as the following solvation layers that show no lateral order. Our experimental results are in excellent agreement with MD

• simulations. The qualitative difference in the lateral order can be understood by the differing chemical environment: While the first layer adopts specific binding positions on the ionic carbonate surface, the second layer resides on top of the organic ethyl layer. A comparison of calcite and magnesite

• has been investigated theoretically by using both density functional theory (DFT) [12][13] and molecular dynamics (MD) simulations [14][15][16][17]. It has been found that ethanol molecules strongly bind towards calcite (10.4) terraces – even stronger than water [12][14][16][17]. Ethanol molecules

Simulations of the 2D self-assembly of tripod-shaped building blocks

• Łukasz Baran,
• Wojciech Rżysko and
• Edyta Słyk

Beilstein J. Nanotechnol. 2020, 11, 884–890, doi:10.3762/bjnano.11.73

• triangular lattice. We have shown that the constraints present in the latter method can enforce the formation of completely different structures, not reproducible with off-lattice simulations. In addition to that, we have characterized the obtained structures regarding various parameters such as theoretical

• diffraction pattern and average association number. Keywords: 2D materials; coarse-grained model; molecular simulations; self-assembly; structural characterization; tripod building blocks; Introduction On-surface synthesis is a newly developing field in chemistry that aims at making use of solid surfaces as

• computer modeling, which allows for a versatile examination of various thermodynamic conditions in acceptable time frames. Additionally, it is also a convenient tool to vary multiple factors such as the shape of the molecules, and the type of solvent and substrate. The insight gained from the simulations

Transition from freestanding SnO₂ nanowires to laterally aligned nanowires with a simulation-based experimental design

• Jasmin-Clara Bürger,
• Sebastian Gutsch and
• Margit Zacharias

Beilstein J. Nanotechnol. 2020, 11, 843–853, doi:10.3762/bjnano.11.69

• Jasmin-Clara Burger Sebastian Gutsch Margit Zacharias Laboratory for Nanotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany 10.3762/bjnano.11.69 Abstract In this study, we used simulations as a guide for

• experiments in order to switch freestanding nanowire growth to a laterally aligned growth mode. By means of finite element simulations, we determined that a higher volumetric flow and a reduced process pressure will result in a preferred laterally aligned nanowire growth. Furthermore, increasing the

• can be changed to the growth of laterally aligned NWs. By comparison of numerical simulations with systematic experiments, we discuss how the process parameters for freestanding SnO2 NWs have to be modified to achieve a laterally aligned NW growth mode. Experimental Substrate preparation The

Integrated photonics multi-waveguide devices for optical trapping and Raman spectroscopy: design, fabrication and performance demonstration

• Gyllion B. Loozen,
• Arnica Karuna,
• Mohammad M. R. Fanood,
• Erik Schreuder and
• Jacob Caro

Beilstein J. Nanotechnol. 2020, 11, 829–842, doi:10.3762/bjnano.11.68

• the influence of surfaces. We report the design (including simulations), fabrication and performance demonstration for multi-waveguide devices, using our Si3N4 waveguiding platform as the basis. The designed ridge waveguides, optimized for trapping and Raman spectroscopy, emit narrow beams. Multiple

• focused Gaussian beam traps and are confirmed by our own simulations. The Raman spectra of the beads (in this work measured via an objective) show clear peaks that are characteristic of polystyrene. In the low-wavenumber range, the spectra have a background that most likely originates from the Si3N4

• maximum obtainable value for the TM polarization, as a result of optimum constructive interference. For transverse electric (TE) polarization, for which the electric field vector of the beams is oriented in the x–y plane, the resulting light concentration is lower. In the simulations, the refractive

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• measurements of single molecules reveal the coexistence of two conformations of molecules on the TiO2 surface. Density functional theory-based simulations (DFT) indicate that the difference originates from the position of the tin atom protruding from the molecule plane. The irreversible switching of Sn-up

• interactions between SnPc molecules and the rutile surface, while DFT-based simulations combined with high-resolution STM images imply that a Sn-down geometry may be preferred as a consequence of steric adjustment between the molecular shape and the corrugated (110) surface. Experimental The experiment was

• creation of additional bonds between the carboxylic groups and the surface. Conclusion The adsorption process of SnPc molecules on the (110) face of rutile TiO2 was studied by microscopic techniques supported by XPS analysis and DFT simulations. At room temperature, single molecules adsorb onto the TiO2

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• relevant property for SPE. The SPE was modeled with a 3-level system with ≈ 2.2 ns, ≈ 2.2 ns and ≈ 67.9 ns. Ab-initio simulations have confirmed that VNNB is likely the color center associated with the SPE [111] (Figure 3), and this defect has been modeled as a candidate to provide optical spin readout

Quantitative determination of the interaction potential between two surfaces using frequency-modulated atomic force microscopy

• Nicholas Chan,
• Carrie Lin,
• Tevis Jacobs,
• Robert W. Carpick and
• Philip Egberts

Beilstein J. Nanotechnol. 2020, 11, 729–739, doi:10.3762/bjnano.11.60

• . It also determines interfacial properties, such as adhesion and friction, and is a key input into mechanics models and atomistic simulations of contacts. We have developed a novel methodology to experimentally determine interaction potential parameters, given a particular potential form, using

• mechanics models [22][23][24][25] to allow better visualization of surface interactions. While useful insights can be obtained using fully atomistic simulations, such as molecular dynamics simulations or density functional theory, these techniques are impractical for describing larger contacts with a large

• representing interactions between mismatched materials, many simulations in tribology and interfacial science also use the LJ potential or potentials based on it [27][28][29][30][31]. However, there is little direct experimental validation of this numerical integration approach. Here, we demonstrate a novel

Effect of Ag loading position on the photocatalytic performance of TiO₂ nanocolumn arrays

• Jinghan Xu,
• Yanqi Liu and
• Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

• between the nanocolumns at the height of 50–120 nm. Figure 8 (b1–4) shows results from the simulations of the ACT3 structure. Ag was filled between the nanocolumns, and a layer of 15 nm thick Ag film was covered on the top of the array. It can be seen from the figure that the Ag coating hinders the

• ) kinetics of different samples, (d) recycling of AFT3 and ACT3. FDTD simulations of the electric field distribution of Ag-loaded TiO2 nanocolumns with different structures. a1) Wavelength 457 nm TNC cross section, a2) wavelength 320 nm TNC cross section, a3) wavelength 457 nm TNC longitudinal section, a4

Stochastic excitation for high-resolution atomic force acoustic microscopy imaging: a system theory approach

• Edgar Cruz Valeriano,
• José Juan Gervacio Arciniega,
• Christian Iván Enriquez Flores,
• Susana Meraz Dávila,
• Joel Moreno Palmerin,
• Martín Adelaido Hernández Landaverde,
• Yuri Lizbeth Chipatecua Godoy,
• Aime Margarita Gutiérrez Peralta,
• Rafael Ramírez Bon and
• José Martín Yañez Limón

Beilstein J. Nanotechnol. 2020, 11, 703–716, doi:10.3762/bjnano.11.58

• modulus in the measurement. In this work, Equation 21 and Equation 27 are useful because these give a quantitative relationship between a set of resonance frequencies and an indentation modulus using white-noise excitation. The validation of this model requires simulations and measurements, which are

• cantilever with L = 400 µm is used and its contact stiffness is changed, it can be seen how the resonance frequencies increase with increasing contact stiffness. Three simulations are shown for contact stiffness values of = 1, 10 and 100 N/m (Figure 4c). The simulation results offer enough support for an

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• substitutional defects (including BC, NC, CB, and CN) at the interface of graphene and boron nitride nanoribbons on the negative differential resistance behavior of the proposed resonant tunneling diode is investigated. Transport simulations are carried out in the framework of tight-binding Hamiltonians and non

• the conduction band edge [40]. Room temperature (300 K) is considered in all simulations. Results and Discussion Substitutional carbon atoms in boron or nitrogen sublattices (CB and CN) as well as boron or nitrogen atoms on carbon sites (BC and NC) are considered (Figure 2). Each defect could occur

Electromigration-induced directional steps towards the formation of single atomic Ag contacts

• Atasi Chatterjee,
• Christoph Tegenkamp and
• Herbert Pfnür

Beilstein J. Nanotechnol. 2020, 11, 680–687, doi:10.3762/bjnano.11.55

• simulations, partly going far beyond the free-electron model, give clear evidence for the existence of quantized conductance in atomic point contacts. The exact conductance values, however, turn out to depend significantly on the local contact configurations so that they may deviate from integer multiples of

• only observed for alkali metals, but also in monovalent noble metals such as Ag and Au [10][11]. These experimental findings could be very well correlated with the theoretical simulations of conductance histograms [7][12][13]. The theoretical calculation of conductance histograms is based on the semi

• can be suppressed to a large extent, in agreement with our own simulations [26]. This situation differs from most previous EM experiments, in which it was difficult to separate EM from thermal effects. For our experiments we use ultrathin Ag films (thickness 5 nm), which exhibit Stranski–Krastanov

A novel dry-blending method to reduce the coefficient of thermal expansion of polymer templates for OTFT electrodes

• Xiangdong Ye,
• Bo Tian,
• Yuxuan Guo,
• Fan Fan and
• Anjiang Cai

Beilstein J. Nanotechnol. 2020, 11, 671–677, doi:10.3762/bjnano.11.53

• the influence of fullerene (C60) on the CTE of Araldite LY 5052/Aradur HY 5052 cross-linked epoxy resin by molecular dynamics simulations. The CTE was minimized by adding a maximum of 15.9 wt % fullerene to the LY/HY/C60 epoxy system. Liu et al. [14] selected MCM-41 mesoporous silica nanoparticles

Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• the nanostructures are calculated by finite-difference time-domain (FDTD) simulations. For calculations a novel approach based on modelling the whole sample with a realistic shape of the nanoparticles, instead of full spheres, was used. This led to a very good agreement with the experiment. Keywords

• shapes. Here, for the first time, a realistic shape of the nanoparticles (according to the TEM images) has been taken into account in the FDTD simulations, instead of modelling them straightforwardly as spheres. Probably the most common example in which the amplification of the local electromagnetic

• ), instead as full spheres, is a novel approach in the present simulations. It is expected, that this procedure should lead to a better agreement with the experiment. The grid size for the computations was set to 4 nm (limited by the available computer memory). The dielectric function of silver and silicon

Current measurements in the intermittent-contact mode of atomic force microscopy using the Fourier method: a feasibility analysis

• Berkin Uluutku and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 453–465, doi:10.3762/bjnano.11.37

• contact-mode imaging. To explore its feasibility, we derive the analytical form of the tip–sample current that would be obtained for attractive (noncontact) and repulsive (intermittent-contact) dynamic AFM characterization, and compare it with results obtained from numerical simulations. Although

• torsional oscillations in a way that reduced cross-contamination of the signals used to reconstruct the tip–sample force. We have also reported numerical simulations of this method, providing analysis software that enables estimations of the accuracy of the method under different conditions [29]. Fourier

• the tunnelling current was neglected. In all cases we obtained good agreement between the analytical expressions derived and the numerical simulations conducted, which suggests that a Fourier-based reconstruction of the current may be feasible. Nevertheless, it is important to point out anticipated

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• structures and MoS2 monolayers is therefore of significant importance and first-principles simulations can probe aspects of this interaction not easily accessible to experiment. Previous theoretical studies have focused particularly on the adsorption of a range of metallic elements, including first-row

Interactions at the cell membrane and pathways of internalization of nano-sized materials for nanomedicine

• Valentina Francia,
• Daphne Montizaan and
• Anna Salvati

Beilstein J. Nanotechnol. 2020, 11, 338–353, doi:10.3762/bjnano.11.25

• interactions is shape. Simulations indicated that based on the energy required for membrane bending, the uptake would be the highest for spheres followed by cubes, then rods, and lastly discs [144]. Nevertheless, a recent in vitro study using gold particles, showed that the number of internalized particles was

• level [109][110]. Simulations showed a higher energy barrier for the internalization of soft and easily deformable nanoparticles than for that of rigid particles [151][152]. However, nanoparticle–cell interactions cannot be described solely by the energy barrier required to bend the lipid membrane

• Section 2.1. Recently, computer simulations and in vitro studies of nanoparticle–membrane interactions have shown that the surface of nanomaterials can in itself induce several changes at the plasma membrane, by determining sol–gel transitions in the lipid bilayer and impairing lipid lateral diffusion

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• the photocharging time is not negligible compared to the light pulse duration. In this case, numerical simulations are necessary to properly analyze the spectroscopic SP(fmod) curves [18]. When investigating organic donor–acceptor (D–A) blends, both capacitive effects and photocharging dynamics shall

Understanding nanoparticle flow with a new in vitro experimental and computational approach using hydrogel channels

• Armel Boutchuen,
• Dell Zimmerman,
• Abdollah Arabshahi,
• John Melnyczuk and
• Soubantika Palchoudhury

Beilstein J. Nanotechnol. 2020, 11, 296–309, doi:10.3762/bjnano.11.22

• different dimension scales of the NPs and the vascular network [18][19][20]. These simulations can essentially be categorized on the basis of details in the physics used to define and model the system [5]. Ab initio quantum mechanical simulations represent the highest level of detail, but are most

• applicable for modeling smaller NP systems or optimizing less detailed simulations due to their increased complexity and computational cost [17]. The coarse grained molecular dynamics simulations can characterize larger systems over time scales greater than 1 ms [21]. These slightly coarser models simulate a

• flow can be a powerful technique for continuum scale simulations of NP flow. The advantage of CFD in comparison to other computationally expensive techniques is the robustness and simplicity of the underlying physics [27][28][29]. CFD methods predict NP flow by solving the fundamental Navier–Stokes

Rational design of block copolymer self-assemblies in photodynamic therapy

• Maxime Demazeau,
• Laure Gibot,
• Anne-Françoise Mingotaud,
• Patricia Vicendo,
• Clément Roux and
• Barbara Lonetti

Beilstein J. Nanotechnol. 2020, 11, 180–212, doi:10.3762/bjnano.11.15

• efficiency using elongated vectors compared to spherical ones [137][138][139]. Simulations [139][140][141] showed that from a thermodynamic standpoint it is always more favorable to encapsulate spherocylindrical particles instead of spheres with the same radius and that endocytosis of spherocylinders occurs

Nonclassical dynamic modeling of nano/microparticles during nanomanipulation processes

• Moharam Habibnejad Korayem,
• Ali Asghar Farid and
• Rouzbeh Nouhi Hefzabad

Beilstein J. Nanotechnol. 2020, 11, 147–166, doi:10.3762/bjnano.11.13

• of nanoparticles. To model this process, previous studies employed classical continuum mechanics and molecular dynamics simulations which had certain limitations; the former does not consider size effects at the nanoscale while the latter is time consuming and faces computational restrictions. To

• . They used the single-walled carbon nanotubes as a probe and performed a series of simulations for studying the effects of various conditions on the success of the nanomanipulation process. They also studied two different strategies for protein manipulation [23]. In another study, using molecular

• potential energy of the beam is more than the adhesion energy the beam tends to retain its straight position [8]. Comparison of the results with other studies Since the validity of the method is mainly dependent on force simulations, the comparison of simulations of critical forces and times with other

Internalization mechanisms of cell-penetrating peptides

• Ivana Ruseska and
• Andreas Zimmer

Beilstein J. Nanotechnol. 2020, 11, 101–123, doi:10.3762/bjnano.11.10

• peptides to directly cross the cellular membranes involves the formation of pores. A theoretical model using molecular dynamics simulations was proposed for the translocation of the TAT peptide, which explains the relevance of peptide–phosphate interaction during the pore formation [47]. This theoretical

The effect of heat treatment on the morphology and mobility of Au nanoparticles

• Sven Oras,
• Sergei Vlassov,
• Simon Vigonski,
• Boris Polyakov,
• Mikk Antsov,
• Vahur Zadin,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2020, 11, 61–67, doi:10.3762/bjnano.11.6

• the geometry from faceted to more rounded shapes were observed with increasing annealing temperature. Kinetic Monte Carlo simulations indicate that the NPs become rounded due to the minimization of the surface area and the transition to lower energy surface types {111} and {100}. The NPs were

• ]. Due to their inert state, geometrical diversity and convenient synthesis, Au NPs are an attractive model system for nanotribological manipulation experiments [5][6][7][8][9][10][11][12] and simulations [13]. Additional flexibility is provided by the ability to tune the properties of the NPs by varying

• Simulations of the NP rounding were carried out using the kinetic Monte Carlo (KMC) code Kimocs [21], which is specifically designed for metal surfaces. The parameters for Au, developed by Vigonski et al. [17], use the tethering method for stabilization [22]. Initially cubic NPs of two sizes with side lengths

An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

• Weili Liu,
• Hongjian Ni,
• Peng Wang and
• Yi Zhou

Beilstein J. Nanotechnol. 2020, 11, 24–40, doi:10.3762/bjnano.11.3

• microstructure, it can be divided into streamwise grooves and transverse grooves. With the development of numerical simulations and experimental techniques, the influence of microstructures on turbulent flow characteristics can be investigated accurately. Its drag reduction mechanism is owed to the two aspects

• measured average pressure difference was compared to the result of numerical simulations at the same flow rate. Figure 9 shows the comparison of the simulated and experimental results, and the maximum relative error was less than 2.0%, which was deemed acceptable. Therefore, it could be concluded from the

• %, which was lower than the maximum DRR of 3.84% obtained in the numerical simulations. Meanwhile, the experimental Reynolds number range associated with a drag reduction effect was smaller than that obtained in the numerical simulation (Table 4). The different results may have been caused by specimen