Tuning the performance of vanadium redox flow batteries by modifying the structural defects of the carbon felt electrode

• Ditty Dixon,
• Deepu Joseph Babu,
• Aiswarya Bhaskar,
• Hans-Michael Bruns,
• Joerg J. Schneider,
• Frieder Scheiba and
• Helmut Ehrenberg

Beilstein J. Nanotechnol. 2019, 10, 1698–1706, doi:10.3762/bjnano.10.165

• Voigt profiles (binding energy (BE) uncertainty: ±0.2 eV). The analyzer transmission function, Scofield sensitivity factors [29], and effective attenuation lengths (EALs) for photoelectrons were applied for quantification. The EALs were calculated using the standard TPP-2M formalism [30]. All spectra

SO₂ gas adsorption on carbon nanomaterials: a comparative study

• Deepu J. Babu,
• Divya Puthusseri,
• Frank G. Kühl,
• Sherif Okeil,
• Michael Bruns,
• Manfred Hampe and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 1782–1792, doi:10.3762/bjnano.9.169

• : ±0.2 eV). The analyzer transmission function, Scofield sensitivity factors [59] and effective attenuation lengths (EALs) for photoelectrons were applied for quantification. The EALs were calculated using the standard TPP-2M formalism [60]. All of the spectra were referenced to the C 1s peak of graphite

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

• Olga E. Glukhova Dmitriy S. Shmygin Saratov State University, Saratov, Russian Federation 10.3762/bjnano.9.117 Abstract We present a new universal method to accelerate calculations of transmission function and electrical conductance of 2D materials, the supercell of which may contain hundreds or

• thousands of atoms. The verification of the proposed method is carried out by exemplarily calculating the electrical characteristics of graphene and graphane films. For the first time, we calculated the transmission function and electrical conductance of pillared graphene, composite film of carbon nanotubes

• (CNTs)/graphene. The electrical conductance of different models of this material was calculated in two mutually perpendicular directions. Regularities in resistance values were found. Keywords: carbon composites; electronic properties; interpolation; quantum transport; transmission function

Thermoelectric current in topological insulator nanowires with impurities

• Sigurdur I. Erlingsson,
• Jens H. Bardarson and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1156–1161, doi:10.3762/bjnano.9.107

• Here fL/R(E) are the Fermi functions for the left/right reservoir with chemical potentials μL/R and temperatures TL/R. We will consider μL = μR = μ. If the transmission function T(E) increases with energy over the integration interval (and the chemical potential is situated somewhere in the interval

• ) the thermoelectric current is positive. This is the normal situation. An anomalous negative current can instead occur if the transmission function decreases with energy. The curve for B = 2.0 T in Figure 2a shows the normal situation where the chemical potential is positioned at an upward step at μ

• = 6.8 meV. The vertical line indicates the position of μ. The resulting charge current is shown in Figure 2b) where the normal situation is evident for B = 2.0 T. If the magnetic field is increased to B = 2.8 T, the energy spectrum changes (not shown) and so will the transmission function T(E). Now a

Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting: combining renewable raw materials with clean fuels

• Stefanie Krüger,
• Michael Schwarze,
• Otto Baumann,
• Christina Günter,
• Michael Bruns,
• Christian Kübel,
• Dorothée Vinga Szabó,
• Rafael Meinusch,
• Verónica de Zea Bermudez and
• Andreas Taubert

Beilstein J. Nanotechnol. 2018, 9, 187–204, doi:10.3762/bjnano.9.21

• 8 eV electrons and low-energy argon ions to prevent any localized charge build-up. The spectra were fitted with one or more Voigt profiles (binding energy uncertainty: ±0.2 eV). The analyzer transmission function, Scofield sensitivity factors [54], and effective attenuation lengths (EALs) for

Gas-sensing behaviour of ZnO/diamond nanostructures

• Marina Davydova,
• Alexandr Laposa,
• Jiri Smarhak,
• Alexander Kromka,
• Neda Neykova,
• Josef Nahlik,
• Jiri Kroutil,
• Jan Drahokoupil and
• Jan Voves

Beilstein J. Nanotechnol. 2018, 9, 22–29, doi:10.3762/bjnano.9.4

• performed using DFT with non-equilibrium Green´s function formalism. The transmission function T(E, V) is a sum of the transmission probabilities of all channels available at energy E and it also depends on bias voltage V. We can apply this function to find the electric current by the Landauer–Buttiker

Fluorination of vertically aligned carbon nanotubes: from CF₄ plasma chemistry to surface functionalization

• Claudia Struzzi,
• Mattia Scardamaglia,
• Jean-François Colomer,
• Alberto Verdini,
• Luca Floreano,
• Rony Snyders and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2017, 8, 1723–1733, doi:10.3762/bjnano.8.173

• by the inelastic mean free path of the electrons and by the transmission function of the spectrometer analyser. The C 1s spectra are characterized by an intense peak associated to the C–C bond in sp2 coordination (located at 284.5 eV). For the functionalized samples, a shoulder appears at about 286

Study of the surface properties of ZnO nanocolumns used for thin-film solar cells

• Neda Neykova,
• Jiri Stuchlik,
• Karel Hruska,
• Ales Poruba,
• Zdenek Remes and
• Ognen Pop-Georgievski

Beilstein J. Nanotechnol. 2017, 8, 446–451, doi:10.3762/bjnano.8.48

• profiles. The analyzer transmission function, Scofield sensitivity factors, and effective attenuation length for photoelectrons were applied for quantification. All spectra were referenced to the adventitious C 1s peak at a binding energy (BE) of 285.0 eV. The BE scale was controlled on standards of poly

Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO₂ nanoparticles on a Si substrate

• Urmas Joost,
• Andris Šutka,
• Meeri Visnapuu,
• Aile Tamm,
• Meeri Lembinen,
• Mikk Antsov,
• Kathriin Utt,
• Krisjanis Smits,
• Ergo Nõmmiste and
• Vambola Kisand

Beilstein J. Nanotechnol. 2017, 8, 229–236, doi:10.3762/bjnano.8.25

• ) procedure [12] and the transmission function of our instrument were used. The raw data were processed using the Casa XPS software [13]. Data processing involved removal of Kα and Kβ satellites, removal of the background and fitting of the components. Background removal was carried out using Tougaard

Role of solvents in the electronic transport properties of single-molecule junctions

• Katharina Luka-Guth,
• Sebastian Hambsch,
• Andreas Bloch,
• Philipp Ehrenreich,
• Bernd Michael Briechle,
• Filip Kilibarda,
• Torsten Sendler,
• Dmytro Sysoiev,
• Thomas Huhn,
• Artur Erbe and
• Elke Scheer

Beilstein J. Nanotechnol. 2016, 7, 1055–1067, doi:10.3762/bjnano.7.99

• dependent transmission function of a scatterer: It assumes that the current is carried by an electronic mode that is formed by a single molecular orbital at energy E0(V), coupled to the left and right electrode via the coupling constants ΓL and ΓR, respectively. The coupling gives rise to broadening of the

• level as described by the Breit–Wigner model yielding a resonance with Lorentzian shape for the transmission function T(E,V) [2][12][27][34][35][36][37]. Here, we expect to find symmetric coupling because of the symmetry of the device being formed by two tips of the same metal and of presumably similar

Thermo-voltage measurements of atomic contacts at low temperature

• Ayelet Ofarim,
• Bastian Kopp,
• Thomas Möller,
• León Martin,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2016, 7, 767–775, doi:10.3762/bjnano.7.68

• Seebeck coefficient S = −ΔV/ΔT, where ΔV is the thermo-voltage and ΔT is the temperature difference. In general S is a function of energy and temperature: Here EF is the Fermi energy, τ(E) is the transmission function, e is the electron charge, kB is the Boltzmann constant and T the temperature of the

• from reduced lifetime, is largely facilitated. Furthermore, temperature-dependent effects of the transmission function that are expected in resonant tunneling situations can be revealed. Thus the ability to measure at variable temperature represents a considerable improvement compared to fixed

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

• below. In the absence of correlations, the retarded Green’s function, GC, remains, like in the equilibrium case, the key quantity allowing for the expression of all the relevant nonequilibrium properties. To illustrate this, the expressions of the transmission function, , local spectral density of

• (entering the expression of the second quantized Hamiltonians, see below), and G< is the so-called lesser Green’s function [16]. The transmission function is given by the trace formula [2][8][17] where the width functions are determined by the imaginary parts of the retarded embedding self-energies

• transmission function [2][8] The difference between the Fermi distributions fL,R(ε) ≡ f(ε − µL,R) of the biased (V ≠ 0) electrodes characterized by unbalanced Fermi energies μL,R = ±eV/2 has an important role (albeit not the only one, see Figure 3 below) in determining the energy window of allowed (elastic

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

• formula, as described in [19]. Here the current I(V) is given by a transmission function T(E, V) through the molecule including contacts between the electrodes, characterized by Fermi functions f for a given voltage V between electrodes and given temperature With the assumption that a single molecular

• orbital with energy E0 governs electronic transmission, the transmission function is given by the Breit–Wigner formula, For the symmetric molecule, the coupling parameters to both sides are equal: Γ = Γ1 = Γ2. Using the single level model, Γ and E0 were varied in order to obtain a best fit to all measured

Simple and efficient way of speeding up transmission calculations with k-point sampling

• Jesper Toft Falkenberg and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2015, 6, 1603–1608, doi:10.3762/bjnano.6.164

• diverging density of states and discontinuities in the transmission function at energies corresponding to band on-sets/channel openings. It is well known that often in order to obtain smooth, well-converged density of states and transmissions as a function of energy, a substantial number of transverse k

• factor of η = 220/41 = 5.37. Transform of data In the following we will outline the method in general terms and denote the data points by (x, y), corresponding to the transmission function data point, (E, Tk(E)), for given k-point and energy in the concrete examples. Initially, we transform the set of

Self-assembled anchor layers/polysaccharide coatings on titanium surfaces: a study of functionalization and stability

• Ognen Pop-Georgievski,
• Dana Kubies,
• Josef Zemek,
• Neda Neykova,
• Roman Demianchuk,
• Eliška Mázl Chánová,
• Miroslav Šlouf,
• Milan Houska and
• František Rypáček

Beilstein J. Nanotechnol. 2015, 6, 617–631, doi:10.3762/bjnano.6.63

• inelastic background subtraction. Assuming a simple model of a semi-infinite solid of homogeneous composition, the peak areas were corrected for the photoelectric cross-sections [63], the inelastic mean free paths of the electrons in question [64], and the transmission function of the spectrometer [65]. The

Study of mesoporous CdS-quantum-dot-sensitized TiO₂ films by using X-ray photoelectron spectroscopy and AFM

• Mohamed N. Ghazzal,
• Robert Wojcieszak,
• Gijo Raj and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 68–76, doi:10.3762/bjnano.5.6

• Equation 1: where σ is the photoionization cross section, T is an instrumental transmission function that reflects the basic detection efficiency, λ is the inelastic mean free path (IMFP) of the primary photoelectrons, and β is an attenuation factor, which is dependent on the particle shape and IMFP. The

Electronic and transport properties of kinked graphene

• Jesper Toft Rasmussen,
• Tue Gunst,
• Peter Bøggild,
• Antti-Pekka Jauho and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2013, 4, 103–110, doi:10.3762/bjnano.4.12

• being M/M/M and SC/M/SC, respectively. For the all-metal pseudo-ribbons, M/M/M, an almost energy-independent transmission function is seen with a transmission close to that of the metallic double-kink in the previous subsection. The SC/M/SC structure shows a transport gap similar to that of the single

• two close-by parallel kinks form a pseudo graphene nanoribbon with similar behaviour of the electronic structure to that for isolated nanoribbons. The transmission function displays transport gap features corresponding to the isolated nanoribbon band gaps. The present work thus suggests that it may be

Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

• Bernd M. Briechle,
• Youngsang Kim,
• Philipp Ehrenreich,
• Artur Erbe,
• Dmytro Sysoiev,
• Thomas Huhn,
• Ulrich Groth and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 798–808, doi:10.3762/bjnano.3.89

• ) coupled via the coupling constants ΓL and ΓR to the left and to the right leads. The coupling results in a broadening of the level and yields a resonance with Lorentzian shape for the transmission function T(E,V) [2][12][32][33][34][41]. In the case of asymmetric coupling, i.e., ΓR ≠ ΓL, the position of

Transmission eigenvalue distributions in highly conductive molecular junctions

• Justin P. Bergfield,
• Joshua D. Barr and
• Charles A. Stafford

Beilstein J. Nanotechnol. 2012, 3, 40–51, doi:10.3762/bjnano.3.5

• transmission matrix [5] where G is the retarded Green’s function [6] of the SMJ, Γα is the tunneling-width matrix describing the bonding of the molecule to lead α, and the total transmission function T(E) = Tr{T(E)}. The number of transmission channels is equal to the rank of the matrix (Equation 1), which is

• approximation is given by where is the dressed tunneling-width matrix, and As evidenced by Equation 14, the isolated-resonance approximation gives an intuitive prediction for the transport. Specifically, the transmission function is a single Lorentzian resonance centered about with a half-width at half

• accuracy of the approximate method shown in Figure 7. Similarly, in the vicinity of the LUMO resonance, the isolated LUMO resonance approximation accurately characterizes the average transmission. The HOMO–LUMO asymmetry in the average transmission function arises because the HOMO resonance couples more

When “small” terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

• Gemma C. Solomon,
• Justin P. Bergfield,
• Charles A. Stafford and
• Mark A. Ratner

Beilstein J. Nanotechnol. 2011, 2, 862–871, doi:10.3762/bjnano.2.95

• electronics; quantum interference; thermoelectrics; topology; Introduction Destructive interference effects, such as nodes in the transmission function, are a signature of coherence and offer a possible avenue for tuning the transport properties of single-molecule junctions. While not present in all systems

• , calculated by means of Hückel theory. All three junctions exhibit a transmission node when E = EF (here set to zero), although the nature of the nodes appears to be different in each case. Using Equation 1 with the Hückel Green’s function, Equation 6, we find that the transmission function of the 1cc

Towards quantitative accuracy in first-principles transport calculations: The GW method applied to alkane/gold junctions

• Mikkel Strange and
• Kristian S. Thygesen

Beilstein J. Nanotechnol. 2011, 2, 746–754, doi:10.3762/bjnano.2.82

• junction are within 0.1 eV of those obtained from accurate grid calculations [24]. The transmission function is obtained from the Meir–Wingreen transmission formula [57][58] The retarded Green’s function of the extended molecule is calculated from Here S, H0, and Vxc are the overlap matrix, Kohn–Sham

• shifted up by 1 eV through a simple scissors-operator self-energy. The transmission function calculated by GW for a coverage of η = 1/16 is shown in Figure 5 on a logarithmic scale. The transmission functions for different molecular lengths have very similar shapes in the important region near the Fermi

• found to decrease in energy by 0.5 eV when n increases from 2 to 6 (Table 2). This shift is indeed visible in the transmission function in the range −4.0 to −6.0 eV where the HOMO is located. On the other hand the features in the transmission function around the Fermi level are determined by the local