Carbon-based smart nanomaterials in biomedicine and neuroengineering

• Antonina M. Monaco and
• Michele Giugliano

Beilstein J. Nanotechnol. 2014, 5, 1849–1863, doi:10.3762/bjnano.5.196

• electronic structure bestows graphene uncommon and astonishing electronic properties, such as the quantum Hall effect, which can be observed even at room temperature [25], a very high electron mobility [26], the ambipolar electric field effect, the ballistic conduction of electronic charge carriers [27], as

Electronic and electrochemical doping of graphene by surface adsorbates

• Hugo Pinto and
• Alexander Markevich

Beilstein J. Nanotechnol. 2014, 5, 1842–1848, doi:10.3762/bjnano.5.195

• for boron, Bs, and nitrogen, Ns, substitutional atoms and leads to p- and n-type conductivity, respectively [15][16]. However, the incorporation of foreign atoms into the graphene lattice can result in a significant modification of the electronic structure of graphene. For instance, Ns-doped graphene

• acid (TPA) or tetracyanoethylene (TCNE) [37][38], shown in Figure 6a and Figure 6b, respectively. After the deposition of TPA, Raman spectroscopic studies showed upshifts of both Raman G and 2D frequencies compared to single layer graphene indicating p-type doping [37]. Electronic structure

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• films. Here, significant progress has been made in free-standing Si NC films [22], but much more effort is needed, for instance by using different electrical characterization techniques, to understand the electrical properties of doped and embedded NCs. III Electronic structure models Effective mass

• understand the trends found by experimental and atomistic modeling studies. More recently, significant understanding of the relationships between structure, chemistry and electronic structure has been obtained from first-principles calculations based on density functional theory. From a theoretical

• Si such transitions are rather unlikely to take place as the large k-space mismatch between conduction band minimum and valence band maximum states implies the involvement of phonons. On the other hand, the dispersionless and tunable nature of the electronic structure of Si NCs holds many promises in

Quasi-1D physics in metal-organic frameworks: MIL-47(V) from first principles

• Danny E. P. Vanpoucke,
• Jan W. Jaeken,
• Stijn De Baerdemacker,
• Kurt Lejaeghere and
• Veronique Van Speybroeck

Beilstein J. Nanotechnol. 2014, 5, 1738–1748, doi:10.3762/bjnano.5.184

• Danny E. P. Vanpoucke Jan W. Jaeken Stijn De Baerdemacker Kurt Lejaeghere Veronique Van Speybroeck Center for Molecular Modeling, Ghent University, Technologiepark 903, Zwijnaarde 9052, Belgium 10.3762/bjnano.5.184 Abstract The geometric and electronic structure of the MIL-47(V) metal-organic

• electronic structure of the different spin configurations is investigated and it shows that the band gap position varies strongly with the spin configuration. The valence and conduction bands show a clear V d-character. In addition, these bands are flat in directions orthogonal to VO6 chains, while showing

• on the geometric and electronic structure is investigated: equilibrium structure, energy, bulk modulus and band structure. Also the transition pressure for the large-pore-to-narrow-pore phase transition is estimated, and inter- and intra-chain coupling constants are calculated. Computational details

On the structure of grain/interphase boundaries and interfaces

• K. Anantha Padmanabhan and
• Herbert Gleiter

Beilstein J. Nanotechnol. 2014, 5, 1603–1615, doi:10.3762/bjnano.5.172

• as vacancies and extra occupancies, are due to the details of the electronic structure requirements and not just structural defects [19][20][21]. In these cases, the formation of structural/basic units will depend on the separation between the atoms and the nature (metallic, ionic or covalent) of the

• missing, e.g., general high-angle grain boundaries [27]. Here it is important to note that in crystalline materials and melt-quenched metallic glasses the electronic structure, if at all different in grain/interphase boundary/interface regions compared with the grain interior, is due to an increase in

Numerical investigation of the effect of substrate surface roughness on the performance of zigzag graphene nanoribbon field effect transistors symmetrically doped with BN

• Majid Sanaeepur,
• Arash Yazdanpanah Goharrizi and
• Mohammad Javad Sharifi

Beilstein J. Nanotechnol. 2014, 5, 1569–1574, doi:10.3762/bjnano.5.168

• ]. Therefore one can model the electronic structure of BN-doped ZGNRs with a first nearest neighbor tight-binding Hamiltonian [34]. The hopping parameters between C, B and N atoms and the on-site energies in place of B and N atoms are set according to [35]. Due to the Gaussian distribution of the experimental

Probing the electronic transport on the reconstructed Au/Ge(001) surface

• Franciszek Krok,
• Mark R. Kaspers,
• Alexander M. Bernhart,
• Marek Nikiel,
• Benedykt R. Jany,
• Paulina Indyka,
• Mateusz Wojtaszek,
• Rolf Möller and
• Christian A. Bobisch

Beilstein J. Nanotechnol. 2014, 5, 1463–1471, doi:10.3762/bjnano.5.159

• transport channel for electrons. Keywords: Au on Ge(001); electronic transport; multi probe STM; scanning tunnelling potentiometry; Introduction Structures consisting of single atoms represent the lower spatial limit for electronic circuits. On such a small scale, the electronic structure is dominated by

• current needs to be coupled to the atomic wires. At neighbouring terraces, the Au/Ge(001) wire structure is rotated by 90° and then a single layer step represents a domain boundary. Simultaneously, also the correlated electronic structure is rotated. Thus, the coupling between adjacent terraces can be

• (001) surface exhibits a two dimensional conductance channel on a micrometre-scale averaging across several Au-reconstructed 1D domains [10]. Scanning tunnelling microscopy (STM) and various STM-based methods are excellent tools to study the topographic structure, the electronic structure, and electron

Liquid fuel cells

• Grigorii L. Soloveichik

Beilstein J. Nanotechnol. 2014, 5, 1399–1418, doi:10.3762/bjnano.5.153

Sublattice asymmetry of impurity doping in graphene: A review

• James A. Lawlor and
• Mauro S. Ferreira

Beilstein J. Nanotechnol. 2014, 5, 1210–1217, doi:10.3762/bjnano.5.133

• interactions between graphene and Al, Ag, Au, Pt(111) substrates, all of which leave the electronic structure intact [61], whilst substrates such as Ni have considerably stronger interactions [62]. Another way to investigate the presence of sublattice asymmetry with dopants other than nitrogen is via ion

DFT study of binding and electron transfer from colorless aromatic pollutants to a TiO₂ nanocluster: Application to photocatalytic degradation under visible light irradiation

• Corneliu I. Oprea,
• Petre Panait and
• Mihai A. Gîrţu

Beilstein J. Nanotechnol. 2014, 5, 1016–1030, doi:10.3762/bjnano.5.115

• nanocluster. To answer the questions raised above we determine the electronic structure and the optical spectra of the pollutant itself, and find where the deprotonation is more likely to take place. We also simulate the pollutant–catalyst system to analyze the binding configurations. We discuss the energy

• focuses on the optimized geometry and electronic structure of the free pollutants. The third subsection presents the binding of the pollutants to the titania nanocluster, the fourth presents the optical properties of the adsorbed pollutants, and the last subsection attempts to explain the experimental

• on the catalyst, the electronic states were accurately computed by using DZVP basis sets [40]. The Gaussian03 package [41] was used in all calculations. Free pollutants – electronic structure and optical properties During the photocatalytic degradation the benzene derivatives (phenol, Ph, benzoic

Growth and characterization of CNT–TiO₂ heterostructures

• Yucheng Zhang,
• Ivo Utke,
• Johann Michler,
• Gabriele Ilari,
• Marta D. Rossell and
• Rolf Erni

Beilstein J. Nanotechnol. 2014, 5, 946–955, doi:10.3762/bjnano.5.108

• . The third mechanism was proposed by Pyrgiotakis [13], in which the C–O–Ti bond introduces energy states in the band gap of TiO2, and is attributed to the extended absorption of longer wavelength light. In addition, they also found that the electronic structure of CNTs may have a bigger effect on the

• -nanometer spatial resolution, which helps to understand the nucleation of diamond [53]. Suenaga et al. have performed in-situ bending of SW-CNTs in TEM and observed a change in the C_K edge ELNES at kinks of the CNT bundles, indicating the change of the electronic structure with the deformation [54

• ]. Theoretical calculations based on density functional theory (DFT) can be used to simulate the details in ELNES and to fundamentally predict the atomic and the electronic structure. Depending on the atomic potentials defined in the calculation, methods based on the band theory, the molecular orbitals or the

An analytical approach to evaluate the performance of graphene and carbon nanotubes for NH₃ gas sensor applications

• Elnaz Akbari,
• Vijay K. Arora,
• Aria Enzevaee,
• Mohamad. T. Ahmadi,
• Mehdi Saeidmanesh,
• Mohsen Khaledian,
• Hediyeh Karimi and
• Rubiyah Yusof

Beilstein J. Nanotechnol. 2014, 5, 726–734, doi:10.3762/bjnano.5.85

• be formed for implementation by applying positive or negative gate voltage and can be useful from the application perspective [35]. Gas molecules can modulate the electronic structure of graphene in diverse ways. The adsorption of CO2 and O2 converts the system to p-type semiconductor while the

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• solution for the photosensitizers to anchor. The hybridization of exfoliated nanosheets with nanosized photosensitizers often shows a tunable electronic structure and new physicochemical properties. All these features attribute to a promising future of nanostructure sensitization in the ion-exchangeable

Constant chemical potential approach for quantum chemical calculations in electrocatalysis

• Wolfgang B. Schneider and
• Alexander A. Auer

Beilstein J. Nanotechnol. 2014, 5, 668–676, doi:10.3762/bjnano.5.79

• applied in the framework of electronic structure theory in order to assess the properties of nanoparticles, nanostructures or interfaces [11][12][13][14][15]. Today, several approaches are available for modelling the full details of the electronic structure in electrochemical phenomena. The most common

• ” [16], and which we previously denoted as “constant charge approach” [13], allows to use the results of a single electronic structure calculation for all potentials [20][21]. Furthermore, this approach is also very convenient for periodic boundary calculations as in this case the models are restricted

• prominent non-faradaic electrochemical modification of catalytic activity (NEMCA) effect [23]. Only in recent years, attempts have been made to go beyond the pure thermodynamical approximation, explicitly including the electrochemical potential into the electronic structure calculation by means of adding or

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• limitation of DFT calculation [63][64]. The electronic structure of Ag2CrO4 indicates that the valence band mainly consists of occupied Ag 4d and O 2p orbitals, and the conduction band mainly comes from the empty Cr 3d orbital, which means that Cr makes an important contribution to the bottom of the

• showed no obvious change when higher cut-off energy and more k-points were adopted. The electronic structure calculation was carried out by using the optimized geometric structure. Measurements of photocatalytic activity The photocatalytic activity of the as-prepared samples was evaluated by the

CoPc and CoPcF₁₆ on gold: Site-specific charge-transfer processes

• Fotini Petraki,
• Heiko Peisert,
• Johannes Uihlein,
• Umut Aygül and
• Thomas Chassé

Beilstein J. Nanotechnol. 2014, 5, 524–531, doi:10.3762/bjnano.5.61

• spectroscopy (UPS) as well as X-ray absorption spectroscopy (XAS). Combined XPS and XAES measurements can be employed as a tool to study the contribution of the polarization energy to chemical shifts at interfaces. XAS gives valuable information about the unoccupied electronic structure and the hybridization

• information about the unoccupied electronic structure is accessible. In Figure 5 we compare F K-edge spectra for two different film thicknesses acquired at a grazing and at a normal incidence of radiation. From N K absorption spectra (data not shown) we conclude that the molecules are flat lying on the

Tensile properties of a boron/nitrogen-doped carbon nanotube–graphene hybrid structure

• Kang Xia,
• Haifei Zhan,
• Ye Wei and
• Yuantong Gu

Beilstein J. Nanotechnol. 2014, 5, 329–336, doi:10.3762/bjnano.5.37

• and can form strong valence bonds with carbon atoms, are the most frequently used doping elements for carbon-based materials [11]. The presence of boron and nitrogen atom induce significant variations in the electronic structure of graphene layer, which was shown by changes in the Raman spectra [12

Atomic layer deposition, a unique method for the preparation of energy conversion devices

• Julien Bachmann

Beilstein J. Nanotechnol. 2014, 5, 245–248, doi:10.3762/bjnano.5.26

• in batteries; ALD for separation and protection, in particular to prevent erosion or corrosion in electrochemical devices; ALD for interface engineering, for example defect passivation in solar cells or prevention of charge recombination by tunnel barriers, and for influencing the electronic

• structure of an underlying semiconductor. This Thematic Series will certainly provide the reader with novel ideas for exploiting ALD in the energy realm, and spur further original work in this rapidly developing research area. After its industrial application in electroluminescent displays, semiconductor

Change of the work function of platinum electrodes induced by halide adsorption

• Florian Gossenberger,
• Tanglaw Roman,
• Katrin Forster-Tonigold and
• Axel Groß

Beilstein J. Nanotechnol. 2014, 5, 152–161, doi:10.3762/bjnano.5.15

• approximately 0.4 ML. By analyzing the underlying electronic structure, we were able to show that this behavior can be explained through a combination of charge transfer and polarization effects of the adsorbate layer. We have now extended this previous study by considering the adsorption of fluorine, chlorine

• halogen adsorption on Pt(111) as a function of the coverage was studied by electronic structure calculations. In general, because of their electronegativity, the adsorption of halogens is associated with a charge transfer from the metal substrate to the adsorbate layer. In the case of fluorine adsorption

Core level binding energies of functionalized and defective graphene

• Toma Susi,
• Markus Kaukonen,
• Paula Havu,
• Mathias P. Ljungberg,
• Paola Ayala and
• Esko I. Kauppinen

Beilstein J. Nanotechnol. 2014, 5, 121–132, doi:10.3762/bjnano.5.12

• have considered either non-periodic (cluster-type) systems or small unit cells. This has made the simulation of extended defects challenging and subject to questionable approximations, and possibly even spurious image–image interaction or finite size effects. Furthermore, the electronic structure of

Influence of the adsorption geometry of PTCDA on Ag(111) on the tip–molecule forces in non-contact atomic force microscopy

• Gernot Langewisch,
• Jens Falter,
• André Schirmeisen and
• Harald Fuchs

Beilstein J. Nanotechnol. 2014, 5, 98–104, doi:10.3762/bjnano.5.9

• tunneling microscopy and scanning tunneling spectroscopy studies of PTCDA adsorbed on Ag(111) have revealed differences in the electronic structure of the molecules depending on their adsorption geometry. In the work presented here, high-resolution 3D force spectroscopy measurements at cryogenic

• simulations, it was found that the differences between the two possible adsorption geometries of PTCDA on the Ag(111) substrate affect the electronic structure of the molecules [2][3][4][5]. The chemical nature of the molecule–substrate bond leads to a charge transfer from the metal surface into the former

• , a significant difference in the intensity of the two adsorption geometries can be observed, which is caused by the different electronic structure as described above. In contrast, this effect is not detectable in the AFM topography image in Figure 1b. However, as discussed above, the reason might be

Quantum size effects in TiO₂ thin films grown by atomic layer deposition

• Massimo Tallarida,
• Chittaranjan Das and
• Dieter Schmeisser

Beilstein J. Nanotechnol. 2014, 5, 77–82, doi:10.3762/bjnano.5.7

• spectroscopy. The Ti precursor, titanium isopropoxide, was used in combination with H2O on Si/SiO2 substrates that were heated at 200 °C. The low growth rate (0.15 Å/cycle) and the in situ characterization permitted to follow changes in the electronic structure of TiO2 in the sub-nanometer range, which are

STM tip-assisted engineering of molecular nanostructures: PTCDA islands on Ge(001):H surfaces

• Amir A. Ahmad Zebari,
• Marek Kolmer and
• Jakub S. Prauzner-Bechcicki

Beilstein J. Nanotechnol. 2013, 4, 927–932, doi:10.3762/bjnano.4.104

• system [20]. Most of the islands have a height of 2.1 nm, what corresponds to 6 molecular layers. Insight into the electronic structure of the studied system is obtained by rt STS measurements (see Figure 1b). For a bare germanium surface a band gap of ≈0.2 eV is obtained, in fair agreement with

• window from −2.5 V to 1.7 V (corresponding to the semiconducting energy gap of PTCDA molecules) of the STS curves. This means that the electronic structure of PTCDA is unperturbed by the electronic properties of the underlying substrate. Figure 1c–f show a set of four consecutive scans of the same area

Adsorption of the ionic liquid [BMP][TFSA] on Au(111) and Ag(111): substrate effects on the structure formation investigated by STM

• Benedikt Uhl,
• Florian Buchner,
• Dorothea Alwast,
• Nadja Wagner and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 903–918, doi:10.3762/bjnano.4.102

• with the surface results in modifications of the electronic structure compared to that in condensed thicker layers. While XPS data exist only for adsorption on Au(111), we expect similar behavior also for adsorption on Ag(111). 2) Upon cooling the sample to 100 K, molecular motion in the adlayer is

Large-scale atomistic and quantum-mechanical simulations of a Nafion membrane: Morphology, proton solvation and charge transport

• Pavel V. Komarov,
• Pavel G. Khalatur and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2013, 4, 567–587, doi:10.3762/bjnano.4.65

• which local density fields are employed as collective variables for simulating the structural evolution of phase-separation morphologies [11][48][49][50][51][52][53]. Several different quantum mechanics approaches have been used in attempts to understand electronic structure and proton conduction in

• redistribution and the change of coordinates of classical atoms, i.e., the Schrödinger and Newton equations are solved in combination at each time step. The approach consists in the determination of forces affecting atoms "on the fly" from electronic structure calculations based on the first (ab initio) quantum

• similar to BOMD, the electrons are kept on the Born–Oppenheimer surface, corresponding to their instantaneous electronic ground state, by means of explicit electronic structure optimization after each MD step [89]. This implies that the time step can be chosen to be as large as the particular ionic