Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• the two organic systems between Au(111) surfaces. The electronic properties of both systems are altered due to the interaction with the gold surface. While in the contact-free CoPc/CoPc stack, the cobalt atoms couple antiferromagnetically, yielding an S = 0 system, the interaction with the gold

Synthesis and catalytic application of magnetic Co–Cu nanowires

• Lijuan Sun,
• Xiaoyu Li,
• Zhiqiang Xu,
• Kenan Xie and
• Li Liao

Beilstein J. Nanotechnol. 2017, 8, 1769–1773, doi:10.3762/bjnano.8.178

• the product of Co nanowires was collected and rinsed three times with deionized water and ethanol, respectively. Next, 0.3 mL of 80 wt % N2H4·H2O were added to the cobalt nanowires with 60 mL of deionized water in a glass beaker, and heated in a water bath at a stationary temperature of 80 °C

• elemental spectrum corresponding to the selected area. Figure 4b shows that the as-prepared product contained elemental cobalt as well as elemental copper, which is in accordance with the XRD patterns. Additionally, silicon, carbon and platinum peaks were from the calculation of the elementary composition

Methionine-mediated synthesis of magnetic nanoparticles and functionalization with gold quantum dots for theranostic applications

• Arūnas Jagminas,
• Agnė Mikalauskaitė,
• Vitalijus Karabanovas and
• Jūrate Vaičiūnienė

Beilstein J. Nanotechnol. 2017, 8, 1734–1741, doi:10.3762/bjnano.8.174

• application of Fe3O4@Met NPs for the adsorption of water pollutants. In this study, we report a novel synthesis protocol for superparamagnetic cobalt ferrite NPs capped with a biocompatible methionine shell (CoFe2O4@Met), which in turn is capable to reduce and attach the gold species. In this way, hybrid

• magneto-plasmonic cobalt ferrite NPs decorated with Au0/Au1+ quantum dots (QDs) were formed for the first time. The formation of plasmonic gold QDs at the surface of iron oxide-based NPs was confirmed by HRTEM, AFM, FTIR, XPS and chemical analysis. Results and Discussion Synthesis and characterization of

• methionine-functionalized cobalt ferrite nanoparticles A hydrothermal approach was applied to synthesize the superparamagnetic cobalt ferrite NPs stabilized with methionine. The proposed approach differs from the reported one [19] in the nature of magnetic NPs, the composition of the aqueous solution applied

Near-infrared-responsive, superparamagnetic Au@Co nanochains

• Varadee Vittur,
• Arati G. Kolhatkar,
• Shreya Shah,
• Irene Rusakova,
• Dmitri Litvinov and
• T. Randall Lee

Beilstein J. Nanotechnol. 2017, 8, 1680–1687, doi:10.3762/bjnano.8.168

• minimally absorbed by tissue chromophores and water [24]. Therefore, tunable plasmonic nanoparticles that can respond to NIR light and can be manipulated with a magnetic field hold great promise. Among various magnetic nanoparticles, cobalt nanoparticles have attracted much interest due to their strong

• magnetic properties and their greater stability toward oxidation compared to Ni- and Fe-based magnetic nanoparticles [23]. Notably, there have been a handful of studies on magneto-optical nanostructures consisting of cobalt coated with gold. Bao and co-workers synthesized magnetic Co–Au core–shell

• nanoparticles [25] by reducing an organo-gold compound onto a cobalt seed with a weak reducing agent in toluene. These particles showed superparamagnetic behavior and a strong optical extinction at ca. 680 nm. Similarly, Wetz and co-workers prepared hybrid Co–Au nanorods via decomposition of an organometallic

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

• Florian Rückerl,
• Daniel Waas,
• Bernd Büchner,
• Martin Knupfer,
• Dietrich R. T. Zahn,
• Francisc Haidu,
• Torsten Hahn and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 1601–1615, doi:10.3762/bjnano.8.160

• ][8]. Phthalocyanine molecules can harbor a number of metal ions, in particular transition-metal ions such as cobalt, iron or manganese. A special characteristic of transition-metal centered phthalocyanines is, that transition-metal ions often are characterized by a magnetic moment, and therefore such

• reaction between F16CoPc and MnPc at the corresponding interface, which affects the cobalt states of F16CoPc. This conclusion is supported by equivalent investigations of CoPc monolayers on gold and silver surfaces, where similar changes in the absorption spectra were observed and where a charge transfer

• between the cobalt 3d states and the underlying metallic substrate occurs [131][132]. Moreover, also the Mn L2,3 absorption edge is subject to substantial changes for MnPc molecules in contact to F16CoPc in comparison to pure MnPc [127]. This provides clear evidence that the charge transfer at the MnPc

Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

• Rasha K. Al-Shewiki,
• Carola Mende,
• Roy Buschbeck,
• Pablo F. Siles,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1191–1204, doi:10.3762/bjnano.8.121

• , which were based on tris(8-hydroxyquinolinato)aluminium (Alq3) sandwiched between La2/3Sr1/3MnO3 and cobalt electrodes, was reported more than a decade ago [5]. This finding motivated the development of further novel devices as, for example, spin-OFETs (organic field effect transistors) [4]. The nature

Preparation of thick silica coatings on carbon fibers with fine-structured silica nanotubes induced by a self-assembly process

• Benjamin Baumgärtner,
• Hendrik Möller,
• Thomas Neumann and
• Dirk Volkmer

Beilstein J. Nanotechnol. 2017, 8, 1145–1155, doi:10.3762/bjnano.8.116

• field of adsorption enable the adaption to catalytic applications [2]. For example, cobalt diselenide nanoparticles can be grafted onto a carbon fiber felt creating a three-dimensional hydrogen evolution cathode based on the high conductivity of carbon fibers [3]. A primary objective of the present

Structural properties and thermal stability of cobalt- and chromium-doped α-MnO₂ nanorods

• Romana Cerc Korošec,
• Polona Umek,
• Alexandre Gloter,
• Jana Padežnik Gomilšek and
• Peter Bukovec

Beilstein J. Nanotechnol. 2017, 8, 1032–1042, doi:10.3762/bjnano.8.104

• presence of Co2+ and Cr3+ ions. Reactions were carried out at three different temperatures: 90, 130 and 170 °C. All prepared samples exhibit a tetragonal MnO2 crystalline phase. SEM–EDS analysis shows that cobalt cations are incorporated to a higher degree into the MnO2 framework than chromium ions, and

• synthesized at 170 °C is significantly lower than in the undoped samples. Analysis of an individual cobalt-doped α-MnO2 nanorod with HAADF-STEM reveals that the distribution of cobalt through the cross-section of the nanorod is uniform. The course of thermal decomposition of the doped nanorods is similar to

• cryptomelane samples exhibit a higher thermal stability than undoped ones. For instance, doping with tin and cobalt shifted the reduction of α-MnO2 to Mn2O3 from 500–550 °C (undoped sample) to 850–900 °C [19][20]. This was ascribed to the incorporation of dopant ions into tunnels stabilizing the structure [19

Needs and challenges for assessing the environmental impacts of engineered nanomaterials (ENMs)

• Michelle Romero-Franco,
• Hilary A. Godwin,
• Muhammad Bilal and
• Yoram Cohen

Beilstein J. Nanotechnol. 2017, 8, 989–1014, doi:10.3762/bjnano.8.101

• inhalation of some ENMs may cause additional adverse outcomes, such as damage to the respiratory tract, inflammation, and activation of signaling pathways. For additional routes of exposure, such as dermal absorption, existing evidence suggests that certain ENMs may penetrate the skin (e.g., cobalt

Nanoantenna-assisted plasmonic enhancement of IR absorption of vibrational modes of organic molecules

• Alexander G. Milekhin,
• Olga Cherkasova,
• Sergei A. Kuznetsov,
• Ilya A. Milekhin,
• Ekatherina E. Rodyakina,
• Alexander V. Latyshev,
• Sreetama Banerjee,
• Georgeta Salvan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2017, 8, 975–981, doi:10.3762/bjnano.8.99

• /bjnano.8.99 Abstract Nanoantenna-assisted plasmonic enhancement of IR absorption and Raman scattering was employed for studying the vibrational modes in organic molecules. Ultrathin cobalt phthalocyanine films (3 nm) were deposited on Au nanoantenna arrays with specified structural parameters. The

• . Keywords: cobalt phthalocyanine; cortisol; localized surface plasmon resonance; metal nanoantennas; Raman scattering; surface-enhanced infrared absorption (SEIRA); Introduction Organic semiconductors have been extensively investigated during the past few decades due to their wide range of applications in

• detection and analysis of vibrational modes of cobalt phthalocyanine deposited on Au nanoantenna arrays. The estimation of the plasmonic enhancement of the fabricated nanoantenna arrays was performed by analyzing the SEIRA and SERS spectra of homogeneous, ultrathin Co Pc films. We also demonstrate SEIRA by

Investigation of growth dynamics of carbon nanotubes

• Marianna V. Kharlamova

Beilstein J. Nanotechnol. 2017, 8, 826–856, doi:10.3762/bjnano.8.85

• intermediate nickel carbide phase in the nickel catalyst [65][69][84]. The presence of intermediate carbide phases was also reported for cobalt catalysts. Buyanov and Chesnokov suggested that the carbide cycle mechanism could be applied to the growth of carbon filaments on all iron-group metal catalysts

• , including cobalt [75]. The authors of recent studies on the growth of nanotubes by the CVD method [65][69][84] also showed that iron, cobalt and nickel catalysts followed a similar reaction path with the formation of intermediate carbide phases during the synthesis process. It should be noted that the

• TEM [52], especially in the case of partial carburization of catalyst particle at its surface [65]. However, in situ TEM confirmed the structure of iron and cobalt carbides when they were the active catalyst phase of the nanotube growth [61][62][81][89][90][91]. Some authors reported that iron carbide

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

• NPs of transition metal (e.g., Co, Ni, Cu, Fe) oxides for LIB applications by using 2 µm cobalt oxide (CoO) particles, achieving an electrochemical capacity of 700 mAh·g−1 with 100% capacity retention for up to 100 cycles [26]. For metal oxide in LIB applications, volume expansion occurs during the Li

• reaction medium due to the presence of the magnetic Fe2O3 NPs. In addition, the materials could be regenerated and utilised via a simple annealing treatment. Cobalt oxide (CoO, Co2O3, Co3O4)–graphene hybrids Cobaltosic oxide (Co3O4)–graphene hybrids can be synthesised by solution methods. Like other hybrid

• plays a role. Mao et al. have prepared 3D crumbled cobalt–GO nanostructure hybrids which show both ORR and oxygen evolution reaction (OER) [171]. Wu et al. have prepared 3D Co3O4/flocculent graphene hybrids on Ni foam for supercapacitor applications as their nanocluster morphology synergistically

Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Riccardo Rossi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 592–603, doi:10.3762/bjnano.8.64

• MWCNTs, for gas sensing applications. Experimental Preparation of metal-decorated MWCNT-based chemiresistors MWCNT networked films were grown by chemical vapor deposition (CVD) directly onto the surface of an alumina substrate that was previously coated with a cobalt (Co) sputtered catalytic layer (≈6 nm

Formation and shape-control of hierarchical cobalt nanostructures using quaternary ammonium salts in aqueous media

• Ruchi Deshmukh,
• Anurag Mehra and
• Rochish Thaokar

Beilstein J. Nanotechnol. 2017, 8, 494–505, doi:10.3762/bjnano.8.53

• (monomers) in presence of quaternary ammonium salts. Hydroxide ions and a magnetic moment of the monomers are essential to induce shape anisotropy in the nanostructures. The cobalt nanoplates are studied in detail, and a growth mechanism based on collision, aggregation, and crystal consolidation is proposed

• of a nanoplate. The study explains, hereto unaddressed, the temporal evolution of complex magnetic nanostructures. These ferromagnetic nanostructures represent an interesting combination of shape anisotropy and magnetic characteristics. Keywords: Brownian motion; cobalt nanoplates; electron

• microscopy; hierarchical nanostructures; magnetic moment; tetramethylazanium hydroxide (TMAH); Introduction The synthesis of ferromagnetic nanomaterials with complex functional architectures has seen rapid development during the past decade [1][2][3]. Cobalt nanostructures form an important class of

Methods for preparing polymer-decorated single exchange-biased magnetic nanoparticles for application in flexible polymer-based films

• Laurence Ourry,
• Delphine Toulemon,
• Souad Ammar and
• Fayna Mammeri

Beilstein J. Nanotechnol. 2017, 8, 408–417, doi:10.3762/bjnano.8.43

• applications. Phosphates and phosphonates are suitable for functionalizing iron and silicon oxide surfaces [29][30] through covalent bonds, in mono-, bi- or tridentate modes; but to date, they have not been used for cobalt oxide and ferrite surfaces. In the case of PMMA, we followed two routes: the first one

• polystyrene: 3024 cm−1 (νas(CH2_arom)), 2950 cm−1 (νs(CH_aliph)) and 1600 cm−1 (νC=C) when compared to a commercial reference. Similar to the PMMA-based nanohybrids, the amount of cobalt was found to be higher than that of iron for PS-functionalized ENPs. The mean free paths of 1.5 nm for iron in CoO and 1.4

• nm for cobalt in CoO were calculated following the method described previously [15]. However, electrons pass only through 0.5 nm of the Fe-rich core after having penetrated the 1 nm thick CoO shell, leading to a difference in depth analysis of the core and the shell. Then, we assumed that cobalt and

Effect of nanostructured carbon coatings on the electrochemical performance of Li_1.4Ni_0.5Mn_0.5O_2+x-based cathode materials

• Konstantin A. Kurilenko,
• Oleg A. Shlyakhtin,
• Oleg A. Brylev,
• Dmitry I. Petukhov and
• Alexey V. Garshev

Beilstein J. Nanotechnol. 2016, 7, 1960–1970, doi:10.3762/bjnano.7.187

• materials; Li-ion batteries; nanocomposites; nanostructures; Introduction LiNi0.5Mn0.5O2-based electrode materials [1] were proposed as a less expensive alternative to LiCoO2 for high energy density Li-ion batteries containing less toxic elements than cobalt. The reasonable combination of their

Ferromagnetic behaviour of ZnO: the role of grain boundaries

• Boris B. Straumal,
• Svetlana G. Protasova,
• Andrei A. Mazilkin,
• Eberhard Goering,
• Gisela Schütz,
• Petr B. Straumal and
• Brigitte Baretzky

Beilstein J. Nanotechnol. 2016, 7, 1936–1947, doi:10.3762/bjnano.7.185

• them with “magnetic” atoms such as iron, manganese and cobalt. Other theoreticians published in that time similar works [2]. It has been predicted that the Curie temperature of such diluted doped magnetic semiconductor oxides can be quite high, even above room temperature. Especially promising was zinc

• growth of single crystals, are well known and well elaborated. It seemed that nothing could prevent the success of the synthesis of ferromagnetic ZnO doped by iron, manganese, cobalt, or other “magnetic” atoms. Indeed first successes came soon. Ferromagnetic ZnO films were synthesised by pulsed laser

• ferromagnetic behaviour of zinc oxide and developed our own method for the synthesis of pure and doped nanocrystalline ZnO films. The obtained data are summarized in Figure 1 for pure ZnO and ZnO doped with manganese, cobalt, iron and nickel [6][7][8][9]. The full list of used references can be found in [6][7

Cubic chemically ordered FeRh and FeCo nanomagnets prepared by mass-selected low-energy cluster-beam deposition: a comparative study

• Veronique Dupuis,
• Anthony Robert,
• Arnaud Hillion,
• Ghassan Khadra,
• Nils Blanc,
• Damien Le Roy,
• Florent Tournus,
• Clement Albin,
• Olivier Boisron and
• Alexandre Tamion

Beilstein J. Nanotechnol. 2016, 7, 1850–1860, doi:10.3762/bjnano.7.177

• ) structure is the equilibrium bulk structure for equimolar FeCo alloys, it was not possible to distinguish a chemical ordering by HRTEM for annealed NPs because the electron density contrast between iron and cobalt is too low. Generally, conventional diffraction measurements are used to determine the degree

• (100) and (012) are clearly visible on the FFT of Figure 4b for annealed FeRh (ΔZFeRh = 19). While in the case of FeCo alloy, the secondary minima are negligible due to the small value of the atomic contrast (ΔZFeCo = 1). Because the nuclear scattering factors for iron and cobalt differ considerably

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• molecules with cobalt atom substituents adsorb most probably in a flat-lying geometry [44], which aligns with the previously discussed case of CuPcs. Similarly, to the CuPcs on the TiO2(011) surface, CoPcs on the (110) face can be classified into two major groups, i.e., those of molecules with Co atoms

Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• (SPIO/oMWCNT#Wu) [38], while Wang used the thermal annealing method of iron(II) acetate (SPIO/oMWCNT#Wang) [43]. Solvothermal co-precipitation of CoCl2 and FeCl3, also by Wu, led to the non-covalent deposition of magnetic cobalt ferrite (CoFe2O4/oMWCNT#Wu) [39]. It was found that a low temperature (180

Customized MFM probes with high lateral resolution

• Óscar Iglesias-Freire,
• Miriam Jaafar,
• Eider Berganza and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2016, 7, 1068–1074, doi:10.3762/bjnano.7.100

• incidence angle, it is possible to cover mainly one side of the tip pyramid. A residual magnetic film with sub-nanometre thickness was found on the remaining parts of the tip–cantilever system. No capping layer is subsequently deposited onto the Co film since, although the outermost atomic layers of cobalt

• applied. This, together with the shape anisotropy induced by the pyramidal tip, forces the magnetic moments to remain mainly oriented along the pyramid surface. Nevertheless, the orientation of the spins at the apex will depend on the apex shape and on the way the cobalt layer covers it. Results and

• estimated for a custom-coated tip with a 25 nm cobalt thickness is less than 25 mT. This value is smaller than any of those reported for different commercial models, making the tips reported here optimal for imaging of soft samples. Finally, similar stray fields than those measured for standard commercial

Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

• Xiaoyu Li,
• Lijuan Sun,
• Hu Wang,
• Kenan Xie,
• Qin Long,
• Xuefei Lai and
• Li Liao

Beilstein J. Nanotechnol. 2016, 7, 990–994, doi:10.3762/bjnano.7.91

• pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth

• surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt

• nanowires are crystalline and mainly consist of cobalt as well as a small amount of platinum. Magnetic measurements showed that the resultant cobalt nanowires were ferromagnetic at room temperature. The saturation magnetization (Ms) and the coercivity (Hc) were 112.00 emu/g and 352.87 Oe, respectively

Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures

• Daniel Lenk,
• Vladimir I. Zdravkov,
• Jan-Michael Kehrle,
• Günter Obermeier,
• Aladin Ullrich,
• Roman Morari,
• Hans-Albrecht Krug von Nidda,
• Claus Müller,
• Mikhail Yu. Kupriyanov,
• Anatolie S. Sidorenko,
• Siegfried Horn,
• Rafael G. Deminov,
• Lenar R. Tagirov and
• Reinhard Tidecks

Beilstein J. Nanotechnol. 2016, 7, 957–969, doi:10.3762/bjnano.7.88

• layer was sputtered from the same target as the metallic Co layer, however, oxygen gas was mixed into the chamber atmosphere to achieve reactive growth of cobalt oxide. For more details on the sputtering procedures see [8][9][41]. The heterostructure obtained was then cut perpendicular to the thickness

• values for the splitting of the metallic and oxide cobalt signals, cross-checked with the RBS spectra for plausibility and slightly adapted to yield the best fit to the RBS spectra. Furthermore, we conducted superconducting quantum interference device (SQUID) magnetometry investigations on several SF1NF2

Magnetic switching of nanoscale antidot lattices

• Ulf Wiedwald,
• Joachim Gräfe,
• Kristof M. Lebecki,
• Maxim Skripnik,
• Felix Haering,
• Gisela Schütz,
• Paul Ziemann,
• Eberhard Goering and
• Ulrich Nowak

Beilstein J. Nanotechnol. 2016, 7, 733–750, doi:10.3762/bjnano.7.65

• films (cf. Figure 5b). All materials show very similar trends. It is noticeable that Py exhibits the smallest coercive fields for all antidot diameters, while the coercive fields for Iron and Cobalt are approximately on the same level for antidot diameters below d = 95 nm. For larger antidots, the

Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures

• Tuan Anh Pham,
• Andreas Schreiber,
• Elena V. Sturm (née Rosseeva),
• Stefan Schiller and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2016, 7, 351–363, doi:10.3762/bjnano.7.32

• gluing unit for the assembly of often linear, hybrid structures of plasmonic gold (Au NP), magnetite (Fe3O4 NP), and cobalt ferrite nanoparticles (CoFe2O4 NP). Furthermore, the assembly of Au NPs into linear structures using Hcp1_cys3 is investigated by UV–vis spectroscopy, TEM and cryo-TEM. One key

• Hcp1_cys3 as a connecting unit is extended to magnetite NPs (Fe3O4 NPs) and cobalt ferrite NPs (CoFe2O4 NPs). The synthesis of magnetite NPs with a size of about 8 nm and the ligand exchange followed the protocol of Cabrera et al. [36], with results as shown in the TEM images of Figure S4, Supporting

• the blank Fe3O4 NPs. A third NP system demonstrates that our concept of the utilization of Hcp1_cys3 as a gluing unit between the NPs to fabricate a linear structure is universal. We synthesized cobalt ferrite NPs (CoFe2O4 NPs) following the protocol of Cabrebra [36] and exchanged the oleic acid