Macromolecular shape and interactions in layer-by-layer assemblies within cylindrical nanopores

• Thomas D. Lazzara,
• K. H. Aaron Lau,
• Wolfgang Knoll,
• Andreas Janshoff and
• Claudia Steinem

Beilstein J. Nanotechnol. 2012, 3, 475–484, doi:10.3762/bjnano.3.54

• behavior, similar to that for a flat surface (Figure 1). Some deviations were observed for the initial deposition steps for the linear-PEs due to differences in the initial surface charge density, i.e., the number of positively charged silanes on alumina versus negatively charged thiols on gold [38]. Then

Reduced electron recombination of dye-sensitized solar cells based on TiO₂ spheres consisting of ultrathin nanosheets with [001] facet exposed

• Hongxia Wang,
• Meinan Liu,
• Cheng Yan and
• John Bell

Beilstein J. Nanotechnol. 2012, 3, 378–387, doi:10.3762/bjnano.3.44

• characteristic temperature that reflects the profile of the charge distribution in TiO2. Therefore, comparison of the change of τn and Dn in DSCs due to the different material composition should be made by using the density of charge as the reference, provided that the distribution profile of charge density is

• TiO2 material. The identical Dn also suggests that the diffusion coefficient of the free electron is the same for the two materials, according to Equation 2 [13]. It also justifies the assumption that the profile of the distribution of charge density is the same in the two types of TiO2 film. In

• kinetics of electron transport and back reaction of the corresponding DSCs is investigated. Figure 5a illustrates the chemical capacitance density of the DSCs made from paste B with and without TiCl4 treatment, as a function of the voltage. It is found that, at a constant charge density, the voltage of the

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

• Adam Sweetman,
• Sam Jarvis,
• Rosanna Danza and
• Philip Moriarty

Beilstein J. Nanotechnol. 2012, 3, 25–32, doi:10.3762/bjnano.3.3

• ), which is suggestive of two atoms terminating the tip and exhibiting radically different interactions with the surface, either due to different elemental composition, or a structurally distorted charge density. It should be noted that thermal drift during these scans was negligible (much less than one

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

• effect than the HOMO–2, which can be understood from the fact that its charge density is located closer to the metallic surfaces. In the limit of an infinitely long wire the HOMO–2 will be spread out over the entire molecule and the image-charge effect should vanish. On the other hand, in this limit the

• HOMO would stay localized near the surface and therefore approach a nonzero constant image charge potential. If we model the HOMO charge density as a point charge of half an electron on each of the amine groups we can estimate this limiting constant to be 3.6/(2d) (eV·Å), where d is the distance to the

Platinum nanoparticles from size adjusted functional colloidal particles generated by a seeded emulsion polymerization process

• Nicolas Vogel,
• Ulrich Ziener,
• Achim Manzke,
• Alfred Plettl,
• Paul Ziemann,
• Johannes Biskupek,
• Clemens K. Weiss and
• Katharina Landfester

Beilstein J. Nanotechnol. 2011, 2, 459–472, doi:10.3762/bjnano.2.50

• dispersion [25][26]. On the other hand, several particle nuclei can cluster together to form a stable particle when the charge density on their surface becomes sufficiently high [25][27][29]. This particle, termed the secondary particle (shown in green color) now participates in the reaction as a new seed

Simulation of bonding effects in HRTEM images of light element materials

• Simon Kurasch,
• Jannik C. Meyer,
• Daniela Künzel,
• Axel Groß and
• Ute Kaiser

Beilstein J. Nanotechnol. 2011, 2, 394–404, doi:10.3762/bjnano.2.45

• ]. Unfortunately it was not possible to extract the total electrostatic potential directly from the pseudopotential calculation as it only offers the self consistent valence charge density but the total charge density is needed. Hence, in a second step, we used the relaxed structure to set up an all electron DFT

• calculation, and therefore we used the WIEN2k [20] DFT software. Furthermore, WIEN2k has the significant advantage that, besides offering access to the total electron charge density and corresponding X-ray scattering factors, in addition, the calculation of the total Coulomb potential (including all electrons

• linearization energies were set automatically. The effect of charge redistribution due to chemical bonding can be studied by comparing the initial charge density (before the first iteration cycle, labeled IAM) and the self-consistent charge density after the WIEN2k calculation has converged (labeled DFT). The

Influence of water on the properties of an Au/Mpy/Pd metal/molecule/metal junction

• Jan Kučera and
• Axel Groß

Beilstein J. Nanotechnol. 2011, 2, 384–393, doi:10.3762/bjnano.2.44

• of the Pdb LDOS is shifted to about −2.35 eV below Ef. Such a strong change of the density of states also indicates a substantial charge transfer between the involved constituents. This is illustrated by the charge density difference isodensity surfaces shown in Figure 5, which correspond to the

• difference between the charge density of the interacting Au/Mpy/Pd/H2O complex and the sum of the charge densities of the isolated Au/Mpy, Pd, and H2O subsystems in the same configuration. There is a strong charge rearrangement along both the N–Pdb and Pdb–O bonds indicative of the covalent character of the

• are marked with arrows. Charge density difference in an isodensity representation calculated as the difference between the charge density of the Au/Mpy/Pd/H2O complex and the sum of the charge densities of the Au/Mpy, Pd, and H2O subsystems. Blue and red surfaces depict the region of charge

The role of the cantilever in Kelvin probe force microscopy measurements

• George Elias,
• Thilo Glatzel,
• Ernst Meyer,
• Alex Schwarzman,
• Amir Boag and
• Yossi Rosenwaks

Beilstein J. Nanotechnol. 2011, 2, 252–260, doi:10.3762/bjnano.2.29

• inhomogeneous sample surface potential. Both the probe and the sample were divided into boundary elements in order to calculate their surface charge density. Unlike our previous work [7], where the probe was divided into conical and spherical elements, here we used commercial software (MSC/Patran®) in order to

• perform fast automatic meshing of an arbitrary probe geometry, including the cantilever as required in this work. The probe charge density was used as the unknown quantity to be determined in order to calculate subsequently the PSF. We use the following notations: (a) A matrix G which is a discrete

• Cinh represents the mutual capacitance density between every pair of surface and probe elements. By inserting the charge density distribution into the Maxwell stress tensor, replacing the probe potential with Vdc(r) + Vac sin(ωt), and extracting the force, we obtained the following expression for the

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• imaged by NC-AFM [25][30] since a color center is a hole in the MgO lattice [22]. The observed attraction of F0 centers originates from the charge density of the two trapped electrons, which are located in the center of the defect site. Due to Coulomb repulsion, the trapped electrons repel each other and

• spill out of the defect site into the vacuum [31]. Therefore, a considerably large charge density is situated above the surface. This charge density is supposed to interact with the tip resulting in a strong attraction, as presented in Figure 7. Since the doubly occupied F0 state is close to the Fermi

• level of the MgO/Ag(001) system [32], the charge density is also responsible for the strong peak in the tunneling current signal. Further insights into the interaction of tip and color center are obtained by periodic supercell DFT calculations at the level of the generalized gradient approximation as

On the reticular construction concept of covalent organic frameworks

• Binit Lukose,
• Agnieszka Kuc,
• Johannes Frenzel and
• Thomas Heine

Beilstein J. Nanotechnol. 2010, 1, 60–70, doi:10.3762/bjnano.1.8

• total energy in the Density-Functional Theory (DFT) with respect to charge density fluctuations. This can be considered as a non-orthogonal tight-binding method parameterized from DFT, which does not require large amounts of empirical parameters, however, maintains all the qualities of DFT. The main