Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• clusters of molecules can be discerned on the terrace without evidence for island formation or decoration of substrate step edges. These observations are indicative of an effectively reduced surface diffusion after adsorption, which lowers the mobility of adsorbed molecules and, thus, the formation of

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• , diffusion coefficient D = kBT/6πηa, and thermodiffusion coefficient DT = STD (here ST is the Soret coefficient) in a solvent of viscosity η we dynamically created high-temperature gradients. To limit diffusion of the particle, one has to create an appropriate temperature gradient ∇T to produce a

• constant force potential at larger distances, which is due to the feedback loop methodology. From the fit of parabolic function U(x) = kx2 we obtained the trap stiffness coefficient k = 1.47kBT/µm2 = 6.0 fN/µm. Larger particles are even easier to trap due to their lower diffusion and higher Soret

• characteristic trapping length from the equilibrium probability density in a temperature field [24], ρ(x) = ρ0exp(−STΔT(x)) = ρ0exp(−ST∇Tx) as A lower temperature gradient therefore implies a less tight trap. Simulation It is clear that the trap stiffness depends on many factors, i.e., the diffusion constant of

Gram-scale synthesis of splat-shaped Ag–TiO₂ nanocomposites for enhanced antimicrobial properties

• Mohammad Jaber,
• Asim Mushtaq,
• Kebiao Zhang,
• Jindan Wu,
• Dandan Luo,
• Zihan Yi,
• M. Zubair Iqbal and
• Xiangdong Kong

Beilstein J. Nanotechnol. 2020, 11, 1119–1125, doi:10.3762/bjnano.11.96

• Gram-positive Staphylococcus aureus (S. aureus) (ATCC 6538) and Gram-negative Escherichia coli (E. coli) (ATCC 8099) were obtained from the Shanghai Amoy Strain Biotechnology Co. (Shanghai, China). The disc diffusion method was applied to check the antibacterial activity of the prepared pure TiO2 NPs

• solution. The antibacterial activity of the TiO2 and Ag–TiO2 NPs was examined by using the disk diffusion method. The sample solutions were prepared separately by using 0.005 g of the TiO2 NPs or Ag–TiO2 nanocomposites in 3 mL of purified water. Afterwards, 6 mm filter paper discs were soaked in the sample

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• kept for storage similar to the Fe collected from dead red blood cells. This can only happen up to the maximum capacity of the spleen [67]. Studying the diffusion of SPIONs in the brain for MRI, Wang and collaborators [128] showed that dextran-coated SPIONs (20 nm) have a good dispersion in the

Plant growth regulation by seed coating with films of alginate and auxin-intercalated layered double hydroxides

• Vander A. de Castro,
• Valber G. O. Duarte,
• Danúbia A. C. Nobre,
• Geraldo H. Silva,
• Vera R. L. Constantino,
• Frederico G. Pinto,
• Willian R. Macedo and
• Jairo Tronto

Beilstein J. Nanotechnol. 2020, 11, 1082–1091, doi:10.3762/bjnano.11.93

• diffusion, reaction rates, and other physicochemical parameters. However, because these substances are sensitive to light and/or temperature variations, their effectiveness for plant growth can be compromised by physical and chemical changes of the medium [13][14][15]. Searching for tools that improve the

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

• Figure 3a) on the sample held at 230 K leads to large densely packed molecular islands on the MoS2 areas (Figure 3b). The large size and high degree of order of these islands reflects a low diffusion barrier on the MoS2 substrate. The moiré pattern of MoS2 remains intact and visible through the molecular

Effect of magnetic field, heat generation and absorption on nanofluid flow over a nonlinear stretching sheet

• Santoshi Misra and
• Govardhan Kamatam

Beilstein J. Nanotechnol. 2020, 11, 976–990, doi:10.3762/bjnano.11.82

• the nanoparticle material and the base fluid. In Equations 1–4, u, and v denote the velocity components along x and y axes, respectively, ρf is the base fluid density, a is a positive constant, DB is the Brownian diffusion coefficient, DT denotes the thermodiffusion coefficient, c is the volumetric

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• anomalously large lifetime, not described by the Kramers’ theory for the escape time over a barrier under the influence of fluctuations. We explain it by the phase diffusion regime, which is evident from the temperature dependence of the switching current histograms. Therefore, phase diffusion allows for a

• through the JJ is observed, which resembles the differentiation between N and N + 1 photon absorption. Keywords: aluminium; Josephson junction; microwaves; phase diffusion; photon counter; switching current distribution; Introduction Currently, an important problem is the creation of single-photon

• critical currents have received a great deal of interest themselves, since they exhibit Josephson phase diffusion [19][20][21][22][23]. The Josephson phase diffusion in small junctions has been studied both experimentally [24][25] and theoretically [26]. Recently, this regime has been observed also in

A 3D-polyphenylalanine network inside porous alumina: Synthesis and characterization of an inorganic–organic composite membrane

• Jonathan Stott and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2020, 11, 938–951, doi:10.3762/bjnano.11.78

• functionalization [33][34]. The surface of ALOX-membranes contains hydroxyl groups, which can be used for chemical modification [35]. Their porosity predetermines different conditions in wet chemical surface functionalization due to a restricted and diffusion limited transport of reactants to the inner surface of

• mechanism [45][47][48]. The degree of carbamic acid salt formation depends on factors like used solvents or CO2 removal during polymerization [49]. Concerning the role of the underlying alumina substrate, we speculate that the CO2 removal within the porous environment by diffusion is very limited and

• %). It has been shown that such mixtures can remove physically adsorbed polypetides on flat surfaces [51]. The treatment was performed by soaking the membranes in the mixture for 18 hours at room temperature. Diffusion limited dissolution of the weakly bonded polymers is the main process of removal of

Key for crossing the BBB with nanoparticles: the rational design

• Sonia M. Lombardo,
• Marc Schneider,
• Akif E. Türeli and
• Nazende Günday Türeli

Beilstein J. Nanotechnol. 2020, 11, 866–883, doi:10.3762/bjnano.11.72

• as (iii) the different nanoparticle types that can be used for drug delivery across the BBB. Review Crossing the BBB Figure 3 describes multiple pathways to cross the BBB. Paracellular pathway and passive transmembrane diffusion The tight junctions between the endothelial cells severely limit the

• diffuse through the BBB by transmembrane diffusion [4]. Furthermore, the BBB endothelial cells have a low degree of pinocytic activity, which again restrains the transport of molecules to the brain [3][8][31]. Transport proteins: carrier-mediated transport and efflux proteins To assure the transport to

• small particles may cross the BBB more easily. Furthermore, after successfully crossing the BBB, size can have an impact on the diffusion of the nanoparticles through the brain extracellular space (ECS). The ECS is a well-connected foam-like structure formed from the interstitial space between neural

A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer

• Pavel M. Marychev and
• Denis Yu. Vodolazov

Beilstein J. Nanotechnol. 2020, 11, 858–865, doi:10.3762/bjnano.11.71

• a single S layer if the thickness of the S and the N layers are about the superconducting coherence length [15]. Because of the large diffusion coefficient, DN ≫ DS, the N layer provides both a large phase concentration in the constriction leading to a single-valued current–phase relation (CPR) and

• change of Δ between consequent iterations is less than 10−4) the Green’s functions are used to calculate js and the supercurrent per unit of width, Is: We also compare the calculated CPR with the CPR of a 1D S’-S-S’ system with a large ratio between the diffusion coefficients DS′/DS ≫ 1 (the length of

• of the superconductor. As we show below, the presence of a relatively thick N layer with large diffusion coefficient and small minigap in the electron spectra provides efficient cooling of the constriction. To estimate the increase of temperature in the resistive state we use a two-temperature (2T

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

• the derived conclusions. We could not find reliable parameters for Sn diffusion, therefore, the parameters for Zn were used (Dn = 1.4 × 10−4 m2/s|1063 K,1 atm, adapted for the given conditions with Equation 1) [27][28]. ZnO NWs can be grown by carbothermal reduction, too [28]. Hence, the simulations

• the powder boat, the metal vapor concentration is homogeneous for all three simulated volumetric flows. In the upstream direction, metal vapor is found, although its concentration is significantly reduced. This is due to the two transport mechanisms of the vapor: diffusion and convection. Equation 1

• presents the pressure and temperature dependence of the diffusion coefficient D, and Equation 2 describes the covered distance as a function of time, t, adapted from [28]: where T and p are the process temperature and the process pressure, respectively, and Dn is the tabular value of the diffusion

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

• spectrally stable with no broadening and limited spectral diffusion, delivering a Fourier transform (FT) limited emission (spectral broadening equal to the inverse of the radiative optical transition lifetime) and thus photon indistinguishability; high purity, i.e., with g(2)(0) close to 0; high brightness

• density of emitters. Such methods based on high-temperature annealing in air and ultraviolet ozone processing are effectively used to improve SP purity (g(2)(0) ≤ 0.1) and the linewidth (FWHM room temperature of ≈3 nm) of the ZPL of CVD-grown h-BN [108]. By control of the boron diffusion through copper

• for practical SPEs. As such SPEs in h-BN have been studied from the point of view of spectral line width, ZPLs at low-temperature distribution, and spectral diffusion by several groups. Since the robustness to temperature is crucial for their practical application, and also the temperature

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

• values of final conductance in about 95% of the structures investigated. We now want to address the question how the thinning process in these morphologically quite different structures proceeds under conditions of EM and at temperatures at which thermal diffusion is largely suppressed [26]. Due to the

• nm wide, the similarity of conductance histograms below 15G0 lead us to the conclusion that only a single contact existed in most cases. A large range of unstable configurations between 14G0 and 5G0 may be characteristic for the EM process at a temperature where only limited thermal diffusion is

Exfoliation in a low boiling point solvent and electrochemical applications of MoO₃

• Matangi Sricharan,
• Bikesh Gupta,
• Sreejesh Moolayadukkam and
• H. S. S. Ramakrishna Matte

Beilstein J. Nanotechnol. 2020, 11, 662–670, doi:10.3762/bjnano.11.52

• could be assigned to the two-dimensional nature of the MoO3 nanosheets, which possess a high surface area allowing for almost unhampered diffusion and electrochemical interaction [29]. To study the effect of exfoliation on the electrochemical properties, bulk MoO3 with 5 wt % of CB was fabricated and

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

• Marta Bartel,
• Katarzyna Markowska,
• Marcin Strawski,
• Krystyna Wolska and
• Maciej Mazur

Beilstein J. Nanotechnol. 2020, 11, 620–630, doi:10.3762/bjnano.11.49

• exposed surface and the retardation of the nanoparticle diffusion caused by aggregation [48]. Some species develop less complicated biofilm structures or even are not capable to form biofilms. The S. epidermidis strain used in our experiments probably does not form complex biofilm structures, as the three

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• storage materials. Here we compare the changes in commercial LiFePO4 cathodes due to ageing and its influence on the measured ESM signal. Additionally, the ESM signal dynamics are analysed to generate characteristic time constants of the diffusion process, induced by a dc-voltage pulse, which changes the

• signal can be found in Supporting Information File 1. Since the variation of the ESM signal is governed by migration and diffusion processes, it can be used to fit relaxation functions and extract the characteristic time constant τ. Diffusion processes are often fitted using an exponential decay function

• and aged LiMnO2 cathodes and found a decrease of the diffusion coefficient in the aged sample due to structural degradation of the material [30]. Zhu et al. studied the degradation of LiNi0.3Co0.3Mn0.3O2 by ESM and showed a decrease in the ESM amplitude over the ageing of the cathode material, which

Luminescent gold nanoclusters for bioimaging applications

• Nonappa

Beilstein J. Nanotechnol. 2020, 11, 533–546, doi:10.3762/bjnano.11.42

• be identical with a fast release up to 6 h and a slow release up to 20 h in PBS buffer, possibly due to diffusion-driven drug release. DPML-MF remained stable in human blood serum up to 24 h. DPML-MF showed a significant effect on HeLa, HepG2 and A375 cell lines with IC50 values 200-fold higher

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

• microparticles (10–200 µm) fabricated via stop flow lithography have emerged as useful templates to form custom-shaped and flexible microcapsules of poly-ʟ-lysine (PLL) [36]. The shell was formed by diffusion of PLL into an oppositely charged hydrogel matrix, enabling an easy surface modification that can be

• , negatively charged probes were permeable into the multilayer films but with a slower diffusion rate. The main advantage of electrostatically bound assemblies is the versatility and high susceptibility towards pH, ionic strength and polarity [43]. As studied under SEM and CLSM, the walls of PAH/PSS

• most commonly used method is the movement of cargo from lower to higher concentration via a concentration gradient based diffusion process such as in case of Dox loading in GA cross-linked (chitosan-alginate)5 microcapsules [76]. At low feeding concentrations (e.g., 750 µg/mL), the drug loading was

Nanoparticles based on the zwitterionic pillar[5]arene and Ag⁺: synthesis, self-assembly and cytotoxicity in the human lung cancer cell line A549

• Dmitriy N. Shurpik,
• Denis A. Sevastyanov,
• Pavel V. Zelenikhin,
• Pavel L. Padnya,
• Vladimir G. Evtugyn,
• Yuriy N. Osin and
• Ivan I. Stoikov

Beilstein J. Nanotechnol. 2020, 11, 421–431, doi:10.3762/bjnano.11.33

• diffusion ordered spectroscopy (DOSY) NMR methods to confirm the formation of associates. There are observed cross peaks between propylene protons of sulfobetaine fragment H8 and ArH protons H1 pillar[5]arene, cross peaks between protons of sulfobetaine fragment H8 and the protons of the methylene bridge H2

• –Ag bond. This hypothesis is in good agreement with the literature data [40][41]. The formation of the 3/Ag+ associate was additionally confirmed by two-dimensional DOSY NMR spectroscopy. The diffusion coefficients of 3 and 3/Ag+ at 298 K (10–3 M) were determined (Figure 4, Supporting Information File

•  1, Table S3). Figure 4 shows that the diffusion coefficients for pillar[5]arene 3 and 3/Ag+ nanoparticles are different. The self-diffusion coefficient of pillar[5]arene 3 is greater (D = 4.22 × 10–10 m2 s−1), which indicates its greater mobility in solution in comparison with 3/Ag+ associates. This

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

• applications. These materials are also interesting as supports for low-dimensional metals for catalysis, while recent work has shown increased interest in using 2D materials in the electronics industry as a Cu diffusion barrier in semiconductor device interconnects. The interaction between different metal

• variety of research areas [1]. These include catalysis [2][3], photonics [4][5], batteries [6], sensors [7][8] and semiconductors and electronics [9][10][11]. More recently, 2D materials have been explored as copper diffusion barriers in CMOS interconnect structures [12][13][14][15]. Furthermore, to

• energy, with binding decreasing as tensile strain increases. While Li can diffuse through the monolayer, the activation energy required is greater than 1 eV and increases with decreasing Se content. Investigation of on-surface diffusion showed that the magnitude of the activation energies is suitable for

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• surface by the ion beam and thermal diffusion of the target atoms. Recently, the gas cluster ion beams (GCIB) technique has been introduced as a mask-free method to produce nanostructures on solid surfaces [11][12]. Among its advantages are the lack of chemical contamination and the low damage to the

• , which are composed of less dense material moved by ion-stimulated diffusion and, second, there are the dark-gray lines of the clean surface representing valleys between the ripples. A further increase of the incidence angle up to 60° results in the further development of the ripples and valleys, i.e

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

• , engineered nano-sized materials can exploit the cellular machinery to be internalized by cells. In fact, since the cell membrane blocks diffusion of complexes larger than ca. 1 kDa, nano-sized materials, such as nanomedicines, are transported into cells using energy-dependent mechanisms, unlike many small

• drugs currently present on the market [5]. This enables nanomedicines to potentially overcome problems associated with the passive diffusion of small molecular drugs through cell membranes, such as their indiscriminate internalization in different cell types and organs, which is often associated with

• 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

• global electrostatic landscape probed by KPFM in the dark state [20]. The photocharging dynamics can be understood as follows. After exciton splitting and dissociation of the charge transfer states at the D–A interfaces, the photogenerated carriers experience a drift-diffusion limited by the carrier

• the 10 nm scale, to maximize the donor–acceptor interfacial area where the excitons are dissociated and to overcome the short-exciton diffusion length. The vast majority of solution-processed D–A blends actually display more complex morphologies. For instance, they can feature a three-component

• optical power. At the lowest fluence applied (Popt = 2.4 mW∙cm−2), the photocharging time even exceeds the pulse duration within the second sequence (Figure 6f). The physics of the photocharging dynamics are based on a drift-diffusion process limited by the carrier mobility. Hence, our data (Figure 6

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

• the measurements of NP flow velocity over seven different mass concentrations. A fully developed laminar flow of the NPs under these conditions was simultaneously predicted using CFD. Results from the mass loss of NPs during flow indicated a diffusion-dominated flow at higher particle concentrations

• in length scale in terms of simulating NP flow through vascular networks for drug delivery. Therefore, continuum models have been explored for NP transport [24]. For example, advection–diffusion models have been applied for transport of NPs through larger vascular constructs where the blood is

• represented as a simple Newtonian fluid [25][26]. The convection–diffusion-reaction continuum models were more suitable in terms of modeling the ligand–receptor binding reactions of NPs in transport through microscale vascular channels. Computational fluid dynamics (CFD), traditionally used in modeling fluid