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

• particular when the monolayer is defect-rich. MoS2 is known to be naturally high in defects [21][32], in particular S vacancies. It has been predicted that S vacancies in a MoS2 monolayer are most stable when they occur in a row, with a decrease in the vacancy formation energy as the number of vacancies

• slightly shorter than the distances in bulk copper. As for the pristine surface, there is no clear correlation between the geometry and the strength of binding. The presence of a defect did not cause any notable geometry distortions in the monolayer. This is supported by Mo–S distances at the copper

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

• “defect” are shown in Figure 6a and the lower inset of Figure 6a, respectively. Whereas, on the nanorod surfaces well-ordered and almost defectless ripples are formed (Figure 6b and Figure 5c,e,f). Similar to the “guiding” effect mentioned above, an ordering effect (at an appropriate fluence) is also

• al. predicting a remarkably defect-free ripple formation on the plane surface by ion bombardment of a binary material should also be noted [10]. In this theory, the composition change of the surface layer by the ion bombardment is discussed and a defect-free ripple formation of an elemental material

• becomes impossible from this point of view. In our experiment we also use binary materials and a defect-free ripple formation is observed, but only for nanorods. However, here, the scenario described in [10] seems unlikely due to a very low energy per atom in the cluster (a few electronvolts) and a

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• ]. It was found that the Kondo resonance is not observed when the Fermi energy is near the Dirac points. The Kondo effect induced by a point defect or a magnetic impurity in graphene has been extensively studied for finite on-site Coulomb interaction within the NRG framework [72][73]. May et al. studied

Size effects of graphene nanoplatelets on the properties of high-density polyethylene nanocomposites: morphological, thermal, electrical, and mechanical characterization

• Tuba Evgin,
• Alpaslan Turgut,
• Georges Hamaoui,
• Zdenko Spitalsky,
• Nicolas Horny,
• Matej Micusik,
• Mihai Chirtoc,
• Mehmet Sarikanat and
• Maria Omastova

Beilstein J. Nanotechnol. 2020, 11, 167–179, doi:10.3762/bjnano.11.14

• graphene or its derivatives have shown that the properties of nanocomposites depend on several factors, such as the polymer type, morphology, intrinsic properties, size and defect level of the filler material, production method, interface between filler and polymer, and others [10][11][12]. Although the

Molecular architectonics of DNA for functional nanoarchitectures

• Debasis Ghosh,
• Lakshmi P. Datta and
• Thimmaiah Govindaraju

Beilstein J. Nanotechnol. 2020, 11, 124–140, doi:10.3762/bjnano.11.11

• compared to ssDNA. The selection of the correct base pairing sequence and order enabled the assembly of DNA with balanced rigidity and flexibility within the nanomaterial systems. The maintenance of an exact stoichiometry and long annealing period were the major criteria to achieve defect-free

Recent progress in perovskite solar cells: the perovskite layer

• Xianfeng Dai,
• Ke Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2020, 11, 51–60, doi:10.3762/bjnano.11.5

• can effectively improve the charge transport efficiency by eliminating the defect and trap density in the perovskite film. The resulting planar PSCs doped with 5 mol % FAAc achieved a PCE of 18.90%, which corresponds to an enhancement of the PCE of over 20% compared to those fabricated by doping with

• because of the unique morphology, which resulted in long carrier lifetime and low defect density. Of course, this precursor solution can be used for slot-die coating to fabricate high-quality PCSs at a high throughput rate. The combination of this special coating solution and the slot-die-coating

Influence of the epitaxial composition on N-face GaN KOH etch kinetics determined by ICP-OES

• Markus Tautz,
• Maren T. Kuchenbrod,
• Joachim Hertkorn,
• Robert Weinberger,
• Martin Welzel,
• Arno Pfitzner and
• David Díaz Díaz

Beilstein J. Nanotechnol. 2020, 11, 41–50, doi:10.3762/bjnano.11.4

• and Al2O3 leads to a high dislocation density, if no strategy for defect reduction is applied. This spans the entire epitaxial layer. The most common strategy to bridge the structural mismatch is the application of AlN and GaN nucleation layers in between the sapphire substrate and bulk GaN [5][6

• ]. Nucleation layers have the second but very important effect of controlling crystal orientation, which is commonly Ga-polar (0001) [7]. Other than nucleation layers, there are several more strategies for defect reduction. These all require the insertion of additional layers or layer transitions into the

Synthesis of amorphous and graphitized porous nitrogen-doped carbon spheres as oxygen reduction reaction catalysts

• Maximilian Wassner,
• Markus Eckardt,
• Andreas Reyer,
• Thomas Diemant,
• Michael S. Elsaesser,
• R. Jürgen Behm and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2020, 11, 1–15, doi:10.3762/bjnano.11.1

• interplanar distance in carbon with a turbostratic structure, and 0.3354 nm for the interplanar distance in a defect-free single crystal of graphite [41][42]. For g-NCS-850 and g-NCS-1000, g values of 0.43 and 0.59 were calculated, respectively. The reflections at 41.2° and 43.6° are associated to the (100

• the number of micropores, and thus of ORR active defect sites. Finally, considering the selectivity for the 4-electron reaction pathway to H2O, which is highly important for technical applications (Figure 8), we find that at potentials below 0.6 V the NCS-1000 catalyst, the best ORR catalyst in this

• directly to one of the N sites, but strongly depends on the amount of defect sites and thus on the microporosity/graphitization of the carbon surface, in combination with a low N-doping. These correlations between structure and ORR activity can be used to further improve the catalytic activity of N-doped

Abrupt elastic-to-plastic transition in pentagonal nanowires under bending

• Sergei Vlassov,
• Magnus Mets,
• Boris Polyakov,
• Jianjun Bian,
• Leonid Dorogin and
• Vahur Zadin

Beilstein J. Nanotechnol. 2019, 10, 2468–2476, doi:10.3762/bjnano.10.237

• at the twin boundaries leads to the brittle fracture-like onset of plastic deformation. The free surface of the NW facilitates the nucleation of defects, such as dislocations in an otherwise practically defect-free pentagonal NW structure. Additional preliminary experiments with alumina-coated Ag NWs

Multiple Fano resonances with flexible tunablity based on symmetry-breaking resonators

• Xiao bin Ren,
• Kun Ren,
• Ying Zhang,
• Cheng guo Ming and
• Qun Han

Beilstein J. Nanotechnol. 2019, 10, 2459–2467, doi:10.3762/bjnano.10.236

• stuctures are investigated at different platforms aiming for Fano resonance. Fano-type transmission phenomenona were observed in photonic crystal (PhC) waveguide–cavity systems [17][18]. The PhC waveguide is a line defect formed by removing a row of rods or air holes. The cavity is a point defect formed by

Mobility of charge carriers in self-assembled monolayers

• Zhihua Fu,
• Tatjana Ladnorg,
• Hartmut Gliemann,
• Alexander Welle,
• Asif Bashir,
• Michael Rohwerder,
• Qiang Zhang,
• Björn Schüpbach,
• Andreas Terfort and
• Christof Wöll

Beilstein J. Nanotechnol. 2019, 10, 2449–2458, doi:10.3762/bjnano.10.235

• ]. Domain boundaries, contaminations and defects have a pronounced, negative effect on charge carrier mobility. This fact calls for measurements on low-defect density samples, preferentially macroscopic single crystals, to determine the intrinsic mobilities. This approach, however, is difficult due to the

• challenge of production and procurement of highly ordered, very pure crystals of macroscopic dimensions with very low defect density, and accordingly only few measurements of such type were reported [5][6][7][8]. Here, we obtain information on intrinsic mobilities, the main figure of merit of OSC materials

• nanometers were formed. This process is expected to lead to rather small 2D domains. Also the exchange of the decanethiolate moieties by HBC may be incomplete, which would also lead to a larger defect density. We speculate that the asymptotic behavior of conductivity increase with island size results from a

pH-Controlled fluorescence switching in water-dispersed polymer brushes grafted to modified boron nitride nanotubes for cellular imaging

• Saban Kalay,
• Yurij Stetsyshyn,
• Volodymyr Donchak,
• Khrystyna Harhay,
• Ostap Lishchynskyi,
• Halyna Ohar,
• Yuriy Panchenko,
• Stanislav Voronov and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2019, 10, 2428–2439, doi:10.3762/bjnano.10.233

• functionalization strategies can be classified into three groups: (1) noncovalent, (2) covalent grafting to the surface, and (3) formation of amino and/or hydroxyl groups at the ends and defect sites [11][25][26][27]. Up to now, the most prospective procedure for BNNT functionalization is covalent grafting of

Deterministic placement of ultra-bright near-infrared color centers in arrays of silicon carbide micropillars

• Stefania Castelletto,
• Abdul Salam Al Atem,
• Faraz Ahmed Inam,
• Hans Jürgen von Bardeleben,
• Sophie Hameau,
• Ahmed Fahad Almutairi,
• Gérard Guillot,
• Shin-ichiro Sato,
• Alberto Boretti and
• Jean Marie Bluet

Beilstein J. Nanotechnol. 2019, 10, 2383–2395, doi:10.3762/bjnano.10.229

• field. Unpaired electrons interact to give two or more energy states [25]. ODMR is a technique to optically pump the electron spin state of a crystal defect for spin initialization and readout [26]. There are over 200 polymorphs of SiC, and the most relevant are cubic SiC (3C) and hexagonal (4H and 6H

• 4H-SiC. The intensity of the largest PL from a single defect at saturation is 10 kcts/s [8] without a solid immersion lens using an a-Si detector with 20–30% quantum efficiency and 40 kcts/s with a solid immersion lens [4]. The DWF is 40%, the ZFS is 70 MHz for V2 and 4 MHz for V1 at the ground state

• permitted to achieve coherent coupling to single nuclear spins with ca. 1 kHz resolution [27]. The divacancy in 4H-SiC is a neutral charge state defect with spin S = 1 with 4 ZPLs PL1–PL4, in the range of 1078–1132 nm [34]. The largest PL intensity is 27 kcps [5] at low temperature using a superconducting

Polyvinylpyrrolidone as additive for perovskite solar cells with water and isopropanol as solvents

• Chen Du,
• Shuo Wang,
• Xu Miao,
• Wenhai Sun,
• Yu Zhu,
• Chengyan Wang and
• Ruixin Ma

Beilstein J. Nanotechnol. 2019, 10, 2374–2382, doi:10.3762/bjnano.10.228

• -Fermi level in the contacted perovskite and electron transfer material, but also by the defect-induced recombination in the electron transport channels [33]. It is clear that perovskite solar cells using a PVP-containing aqueous lead nitrate precursor solution will lead to an increase in Voc. The Voc of

Design and facile synthesis of defect-rich C-MoS₂/rGO nanosheets for enhanced lithium–sulfur battery performance

• Chengxiang Tian,
• Juwei Wu,
• Zheng Ma,
• Bo Li,
• Pengcheng Li,
• Xiaotao Zu and
• Xia Xiang

Beilstein J. Nanotechnol. 2019, 10, 2251–2260, doi:10.3762/bjnano.10.217

• composite with both large surface area and high porosity for the use as advanced electrode material in lithium–sulfur batteries. Double modified defect-rich MoS2 nanosheets are successfully prepared by introducing reduced graphene oxide (rGO) and amorphous carbon. The conductibility of the cathodes can be

• catalyzing the formation of sulfur species [21][22], indicating a potential application for Li–S batteries. Previous simulation results show that the binding energy of the edge active sites of defect-rich MoS2 and Li2S is much greater than the binding energy of the base plane, which is very helpful for the

• adsorption of polysulfides [23][24]. However, the low conductivity of MoS2 often results in incomplete conversion of polysulfides. Thus, MoS2 is usually combined with carbon materials and annealing treatment is also considered [25][26]. Hence, double modification of defect-rich MoS2 nanosheets with amorphous

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

• and Technology, University of Wales, Wrexham, United Kingdom Department of Computer Science, University of Western Cape, Cape Town, South Africa School of Engineering, RMIT University, Bundoora, Victoria, Australia 10.3762/bjnano.10.207 Abstract The nitrogen-vacancy (NV) center is a point defect in

• illumination [7]. The characterization of single NV centers became popular at the end of the 1990s. It was demonstrated that the fluorescence of single NV centers can be detected by room-temperature fluorescence microscopy and that the defect shows perfect photostability [8]. Room-temperature optically

• associated with NV center sensors for magnetic imaging applications. An NV center is an atomic size point defect in diamond. Standard optical techniques are capable of resolving the photoluminescence signal of a single NV center, the detection of which is facilitated particularly in the negative charge state

Ion mobility and material transport on KBr in air as a function of the relative humidity

• Dominik J. Kirpal,
• Korbinian Pürckhauer,
• Alfred J. Weymouth and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2019, 10, 2084–2093, doi:10.3762/bjnano.10.203

• removed material accumulated around the defect and to a small extent attached to the tip. Most of the material accumulates at the turnaround points of the tip. The scratching technique creates larger and more reproducible holes than the poking of single points, since the shape of the tip becomes less

• . The depth of the defects is defined by the height difference between the lowest point of the defect and the surrounding terrace. The removed material aggregates around the artificial defect. The accumulations do not attach symmetrically but irregularly around the holes. This can be explained by the

• model as described in Ref. [29]. If we were to start with a defect that has the first layer removed in a circle with radius R1 and a second (deeper) layer removed in a circle with radius r1< R1, this would yield an energy term for the edge E1 ∝ 2πR1 + 2πr1. The defect now evolves, maintaining the total

Green and scalable synthesis of nanocrystalline kuramite

• Andrea Giaccherini,
• Giuseppe Cucinotta,
• Stefano Martinuzzi,
• Enrico Berretti,
• Werner Oberhauser,
• Alessandro Lavacchi,
• Giovanni Orazio Lepore,
• Giordano Montegrossi,
• Maurizio Romanelli,
• Antonio De Luca,
• Massimo Innocenti,
• Vanni Moggi Cecchi,
• Matteo Mannini,
• Antonella Buccianti and
• Francesco Di Benedetto

Beilstein J. Nanotechnol. 2019, 10, 2073–2083, doi:10.3762/bjnano.10.202

• covellite in the final product, a relevant factor is the molar defect of Cu precursor in the EG. The crystal chemical analysis (by Raman, XRD and EXAFS) revealed a random distribution of antisite defects, SnCu and CuSn, in the tetragonal structure while still maintaining the I−42m symmetry. These chemical

Improvement of the thermoelectric properties of a MoO₃ monolayer through oxygen vacancies

• Wenwen Zheng,
• Wei Cao,
• Ziyu Wang,
• Huixiong Deng,
• Jing Shi and
• Rui Xiong

Beilstein J. Nanotechnol. 2019, 10, 2031–2038, doi:10.3762/bjnano.10.199

• supercell (72 atoms) to construct a neutral defect, such that the stoichiometric proportion is MoO2.94. Since there are three types of O atoms in the primitive cell, we named the three defective structures VO1, VO2 and VO3. Further details of the defect structures are presented in Supporting Information

• File 1. The formation energy, Ef, of a neutral defect is defined as: Ef = Etot(defect) − Etot(supercell) + ½ Etot(O2), where Etot(defect) is the total energy of the supercell containing the defect, Etot(supercell) is the total energy of the perfect supercell and Etot(O2) is the total energy of the

• oxygen molecules. Then we calculate the formation energies and band gaps of these defect structures. The absolute Ef values are 2.074 eV (VO1), 2.076 eV (VO2) and 4.108 eV (VO3) while the band gaps are 0.837 eV (VO1), 0.797 eV (VO2) and 0.831 eV (VO3). In contrast to the bulk MoO3, the three defective

The influence of porosity on nanoparticle formation in hierarchical aluminophosphates

• Matthew E. Potter,
• Lauren N. Riley,
• Alice E. Oakley,
• Panashe M. Mhembere,
• June Callison and
• Robert Raja

Beilstein J. Nanotechnol. 2019, 10, 1952–1957, doi:10.3762/bjnano.10.191

• (Figure S4 and Figure S5, Supporting Information File 1), the decrease in porosity suggests that the 1D channels are blocked, restricting access to the internal micropores. As pore mouths are known to produce high-energy defect sites [18], they are more likely to encourage nanoparticle deposition, thus

First principles modeling of pure black phosphorus devices under pressure

• Ximing Rong,
• Zhizhou Yu,
• Zewen Wu,
• Junjun Li,
• Bin Wang and
• Yin Wang

Beilstein J. Nanotechnol. 2019, 10, 1943–1951, doi:10.3762/bjnano.10.190

• to 40%, which indicates the stability of monolayer BP under zero pressure. The smooth variation of Etot means that monolayer BP can maintain its structure even at large pressure, and does not form any structural defect or bonding twist. The stress Ps can be calculated by Ps = −∂Etot/∂d·1/S with d the

Fabrication and characterization of Si_1−xGe_x nanocrystals in as-grown and annealed structures: a comparative study

• Muhammad Taha Sultan,
• Adrian Valentin Maraloiu,
• Ionel Stavarache,
• Jón Tómas Gudmundsson,
• Andrei Manolescu,
• Valentin Serban Teodorescu,
• Magdalena Lidia Ciurea and
• Halldór Gudfinnur Svavarsson

Beilstein J. Nanotechnol. 2019, 10, 1873–1882, doi:10.3762/bjnano.10.182

• the SiGe NCs); these defects do not appear because other relaxation processes take place as shown earlier. Since these shearing defects are near or in the (111) stacking planes of the SiGe structure, the NC size along the direction that is parallel to the defect plane remains large and the two others

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

• the carbon felt. Moreover, the D-band of the plasma-treated sample was shifted to a higher frequency, indicating an increase in the defect density. Mostly, this increase in defects can be correlated to heteroatom substitution/doping (N-doping) and the simultaneous creation of new edge sites [17]. At

Subsurface imaging of flexible circuits via contact resonance atomic force microscopy

• Wenting Wang,
• Chengfu Ma,
• Yuhang Chen,
• Lei Zheng,
• Huarong Liu and
• Jiaru Chu

Beilstein J. Nanotechnol. 2019, 10, 1636–1647, doi:10.3762/bjnano.10.159

• calculations provide a guide to optimizing parameter settings for the nondestructive diagnosis of flexible circuits. Defect detection of the embedded circuit pattern was also carried out, which indicates the capability of imaging tiny subsurface structures smaller than 100 nm by using CR-AFM. Keywords: atomic

• force microscopy (AFM); contact resonance atomic force microscopy (CR-AFM); contact stiffness; defect detection; flexible circuits; subsurface imaging; Introduction With the rapid shrinkage of microelectronic devices, flexible circuits are intensively used while being functionalized as supercapacitors

• been carried out using CR-AFM for subsurface imaging, its application in defect diagnosis for flexible circuits has seldom been reported. Intuitively, the presence of buried metal circuit patterns in the tip-generated stress field will alter the local indentation modulus. This consequently leads to

Hierarchically structured 3D carbon nanotube electrodes for electrocatalytic applications

• Pei Wang,
• Katarzyna Kulp and
• Michael Bron

Beilstein J. Nanotechnol. 2019, 10, 1475–1487, doi:10.3762/bjnano.10.146

• carbon, respectively [64]. The intensity ratios of these bands (ID/IG) for the CNT/GC und CNT/CNT/GC electrodes are 1.36 und 1.54, respectively. This indicates that the secondary CNTs are less ordered and have a higher defect density than the primary ones. As the last step in electrode preparation, Pt

• -oxidation of COad compared to Pt-CNT/GC The reason for this improved poisoning tolerance is not known to us at the moment. However, it is known from literature that methanol as well as CO oxidation are very sensitive to Pt surface structure. It might be that a defect-rich structure of our Pt nanoparticles

• oxygen reduction reaction. Although there are differences in electrode preparation (in the present case, Pt is electrodeposited onto the carbon-based electrodes, probably leading to defect-rich particles (see also below), while in [52], Pt deposition has been deposited by CVD), we think that generally