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Beilstein Journal of Nanotechnology

Amelie Axt, Ilka M Hermes, Victor W Bergmann, Niklas Tausendpfund, Stefan A L Weber
In this study we investigate the influence of the operation method in Kelvin probe force microscopy (KPFM) on the measured potential distribution. KPFM is widely used to map the nanoscale potential distribution in operating devices, e.g., in thin film transistors or on cross sections of functional solar cells. Quantitative surface potential measurements are crucial for understanding the operation principles of functional nanostructures in these electronic devices. Nevertheless, KPFM is prone to certain imaging artifacts, such as crosstalk from topography or stray electric fields...
2018: Beilstein Journal of Nanotechnology
Katherine Atamanuk, Justin Luria, Bryan D Huey
The nanoscale optoelectronic properties of materials can be especially important for polycrystalline photovoltaics including many sensor and solar cell designs. For thin film solar cells such as CdTe, the open-circuit voltage and short-circuit current are especially critical performance indicators, often varying between and even within individual grains. A new method for directly mapping the open-circuit voltage leverages photo-conducting AFM, along with an additional proportional-integral-derivative feedback loop configured to maintain open-circuit conditions while scanning...
2018: Beilstein Journal of Nanotechnology
Caihong Liang, Jiang Wen, Xiaoming Liao
In this work, a visible-light-controlled drug release platform was constructed for localized and prolonged drug release based on two-layer titania nanotubes (TNTs) fabricated using by an in situ voltage up-anodization process. The visible-light photocatalytic activity is improved by loading Ag onto the TNTs by NaBH4 reduction. Then, the TNTs containing Ag nanoparticles were modified with dodecanethiol (NDM) to create a hydrophobic layer. To demonstrate the visible-light-controlled drug release, the Zn2+ release behavior of the samples was investigated...
2018: Beilstein Journal of Nanotechnology
Deepu J Babu, Divya Puthusseri, Frank G Kühl, Sherif Okeil, Michael Bruns, Manfred Hampe, Jörg J Schneider
Owing to their high stability against corrosive gases, carbon-based adsorbents are preferentially used for the adsorptive removal of SO2 . In the present study, SO2 adsorption on different carbon nanomaterials namely carbon nanohorns (CNHs), multiwalled carbon nanotubes (MWNTs), single-walled carbon nanotubes (SWNTs) and vertically aligned carbon nanotubes (VACNTs) are investigated and compared against the adsorption characteristics of activated carbon and graphene oxide (GO). A comprehensive overview of the adsorption behavior of this family of carbon adsorbents is given for the first time...
2018: Beilstein Journal of Nanotechnology
Can Zhao, Yuexiao Song, Tianyu Xiang, Wenxiu Qu, Shuo Lou, Xiaohong Yin, Feng Xin
Novel hexagonal nanoplates (NPLs) comprised of mesoporous carbon containing imbedded magnetic Co nanoparticles (CoAl2 O4 phase) are prepared through direct carbonization of polydopamine (PDA)-coated CoAl layered double hydroxide (LDH). A uniform PDA coating initially covers the surface of LDH by dopamine self-polymerization under mild conditions. Well-dispersed Co nanoparticles are formed in the NPLs by the partial reduction of cobalt from Co2+ to Co0 with surface carbon during the heat treatment process. The surface morphology and specific surface area of the as-prepared NPLs can be tailored by adjusting the initial dopamine concentration and carbonization temperature...
2018: Beilstein Journal of Nanotechnology
Andrey A Kamashev, Aidar A Validov, Joachim Schumann, Vladislav Kataev, Bernd Büchner, Yakov V Fominov, Ilgiz A Garifullin
We have studied superconducting properties of spin-valve thin-layer heterostructures CoO x /F1/Cu/F2/Cu/Pb in which the ferromagnetic F1 layer was made of Permalloy while for the F2 layer we have taken a specially prepared film of the Heusler alloy Co2 Cr1- x Fe x Al with a small degree of spin polarization of the conduction band. The heterostructures demonstrate a significant superconducting spin-valve effect, i.e., a complete switching on and off of the superconducting current flowing through the system by manipulating the mutual orientations of the magnetization of the F1 and F2 layers...
2018: Beilstein Journal of Nanotechnology
Elena A Trusova, Nikolai S Trutnev
In the present investigation, the cryochemical approach was used for the improved synthesis of nanocrystalline metal oxides (e.g., NiO, Fe2 O3 , CeO2 ) and NaNO3 salt. It was shown that the solutions and sols can be treated with a liquid nitrogen stream (-196 °C) to increase the powder dispersity by 3-18 times and to increase their specific surface area by an order of magnitude. The proposed approach also reduces the agglomeration of the nanoparticles, and at the same time, results in NiO, Fe2 O3 and CeO2 crystallite sizes of less than 10 nm (quantum dot size regime)...
2018: Beilstein Journal of Nanotechnology
Reika Makita, Tsukasa Akasaka, Seiichi Tamagawa, Yasuhiro Yoshida, Saori Miyata, Hirofumi Miyaji, Tsutomu Sugaya
Background: Collagen is a basic component of the periodontium and plays an important role in the function of the periodontal unit. Therefore, coating with collagen/gelatin has been applied to enable dental implants to positively interact with peri-implant tissues. Although the micro/nanoscale topography is an important property of the surface of dental implants, smaller collagen/gelatin surface patterns have not been sufficiently developed. Furthermore, only few reports on the behavior of cells on gelatin surfaces with different patterns and sizes exist...
2018: Beilstein Journal of Nanotechnology
Juan L Palma, Alejandro Pereira, Raquel Álvaro, José Miguel García-Martín, Juan Escrig
Magnetic films of magnetite (Fe3 O4 ) with controlled defects, so-called antidot arrays, were synthesized by a new technique called AFIR. AFIR consists of the deposition of a thin film by atomic layer deposition, the generation of square and hexagonal arrays of holes using focused ion beam milling, and the subsequent thermal reduction of the antidot arrays. Magnetic characterizations were carried out by magneto-optic Kerr effect measurements, showing the enhancement of the coercivity for the antidot arrays...
2018: Beilstein Journal of Nanotechnology
Jong Tae Moon, Seung Ki Lee, Ji Bong Joo
This study reports on the controllable synthesis of uniform colloidal titanium dioxide (TiO2 ) particles and their photocatalytic applications toward rhodamine B (RhB) degradation. The monodispersed TiO2 particles were synthesized under mixed solvent conditions by sol-gel chemistry in a one-pot process. Varying the ratio of solvent composition, the concentration of surfactant and TiO2 precursor was used to control the particle diameter, degree of monodispersity and morphology. The modification of the calcination temperature affected the crystallinity and crystalline phase of the colloidal TiO2 particles...
2018: Beilstein Journal of Nanotechnology
Pasquale Marra, Alessandro Braggio, Roberta Citro
The classification of topological states of matter in terms of unitary symmetries and dimensionality predicts the existence of nontrivial topological states even in zero-dimensional systems, i.e., systems with a discrete energy spectrum. Here, we show that a quantum dot coupled with two superconducting leads can realize a nontrivial zero-dimensional topological superconductor with broken time-reversal symmetry, which corresponds to the finite size limit of the one-dimensional topological superconductor. Topological phase transitions corresponds to a change of the fermion parity, and to the presence of zero-energy modes and discontinuities in the current-phase relation at zero temperature...
2018: Beilstein Journal of Nanotechnology
Yann Almadori, David Moerman, Jaume Llacer Martinez, Philippe Leclère, Benjamin Grévin
In this work, methylammonium lead tribromide (MAPbBr3 ) single crystals are studied by noncontact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM). We demonstrate that the surface photovoltage and crystal photostriction can be simultaneously investigated by implementing a specific protocol based on the acquisition of the tip height and surface potential during illumination sequences. The obtained data confirm the existence of lattice expansion under illumination in MAPbBr3 and that negative photocarriers accumulate near the crystal surface due to band bending effects...
2018: Beilstein Journal of Nanotechnology
Geetanjali Deokar, Nitul S Rajput, Junjie Li, Francis Leonard Deepak, Wei Ou-Yang, Nicolas Reckinger, Carla Bittencourt, Jean-Francois Colomer, Mustapha Jouiad
Densely populated edge-terminated vertically aligned two-dimensional MoS2 nanosheets (NSs) with thicknesses ranging from 5 to 20 nm were directly synthesized on Mo films deposited on SiO2 by sulfurization. The quality of the obtained NSs was analyzed by scanning electron and transmission electron microscopy, and Raman and X-ray photoelectron spectroscopy. The as-grown NSs were then successfully transferred to the substrates using a wet chemical etching method. The transferred NSs sample showed excellent field-emission properties...
2018: Beilstein Journal of Nanotechnology
Yan Zhao, Zhengjun Liu, Liancheng Sun, Yongguang Zhang, Yuting Feng, Xin Wang, Indira Kurmanbayeva, Zhumabay Bakenov
Nitrogen-doped carbon nanotubes coated with zinc oxide nanoparticles (ZnO@NCNT) were prepared via a sol-gel route as sulfur encapsulator for lithium/sulfur (Li/S) batteries. The electrochemical properties of the S/ZnO@NCNT composite cathode were evaluated in Li/S batteries. It delivered an initial capacity of 1032 mAh·g-1 at a charge/discharge rate of 0.2C and maintained a reversible capacity of 665 mAh·g-1 after 100 cycles. The coulombic efficiency of the cathode remains unchanged above 99%, showing stable cycling performance...
2018: Beilstein Journal of Nanotechnology
Alex Zazunov, Albert Iks, Miguel Alvarado, Alfredo Levy Yeyati, Reinhold Egger
We present a theoretical analysis of the equilibrium Josephson current-phase relation in hybrid devices made of conventional s -wave spin-singlet superconductors (S) and topological superconductor (TS) wires featuring Majorana end states. Using Green's function techniques, the topological superconductor is alternatively described by the low-energy continuum limit of a Kitaev chain or by a more microscopic spinful nanowire model. We show that for the simplest S-TS tunnel junction, only the s -wave pairing correlations in a spinful TS nanowire model can generate a Josephson effect...
2018: Beilstein Journal of Nanotechnology
Christiane Petzold, Marcus Koch, Roland Bennewitz
Friction force microscopy was performed with oxidized or gold-coated silicon tips sliding on Au(111) or oxidized Si(100) surfaces in ultrahigh vacuum. We measured very low friction forces compared to adhesion forces and found a modulation of lateral forces reflecting the atomic structure of the surfaces. Holding the force-microscopy tip stationary for some time did not lead to an increase in static friction, i.e., no contact ageing was observed for these pairs of tip and surface. Passivating layers from tip or surface were removed in order to allow for contact ageing through the development of chemical bonds in the static contact...
2018: Beilstein Journal of Nanotechnology
Chunmei Zhang, Yalong Jiao, Fengxian Ma, Sri Kasi Matta, Steven Bottle, Aijun Du
The detection of single gas molecules is a highly challenging work because it requires sensors with an ultra-high level of sensitivity. By using density functional theory, here we demonstrate that the adsorption of a paramagnetic unpaired free radical gas (NO) on a monolayer of XS2 (X = Mo, W) can trigger the transition from semiconductor to half metal. More precisely, the single-layer XS2 (X = Mo, W) with NO adsorbed on it would behave like a metal in one spin channel while acting as a semiconductor in the other spin orientation...
2018: Beilstein Journal of Nanotechnology
Boštjan Žener, Lev Matoh, Giorgio Carraro, Bojan Miljević, Romana Cerc Korošec
Titanium dioxide photocatalysts have received a lot of attention during the past decades due to their ability to degrade various organic pollutants to CO2 and H2 O, which makes them suitable for use in environmental related fields such as air and water treatment and self-cleaning surfaces. In this work, titania thin films and powders were prepared by a particulate sol-gel route, using titanium tetrachloride (TiCl4 ) as a precursor. Afterwards, the prepared sols were doped with nitrogen (ammonium nitrate, urea), sulfur (thiourea) and platinum (chloroplatinic acid), coated onto glass substrates by dip-coating, and thermally treated in a muffle furnace to promote crystallization...
2018: Beilstein Journal of Nanotechnology
Jonathan Op de Beeck, Nouha Labyedh, Alfonso Sepúlveda, Valentina Spampinato, Alexis Franquet, Thierry Conard, Philippe M Vereecken, Wilfried Vandervorst, Umberto Celano
The continuous demand for improved performance in energy storage is driving the evolution of Li-ion battery technology toward emerging battery architectures such as 3D all-solid-state microbatteries (ASB). Being based on solid-state ionic processes in thin films, these new energy storage devices require adequate materials analysis techniques to study ionic and electronic phenomena. This is key to facilitate their commercial introduction. For example, in the case of cathode materials, structural, electrical and chemical information must be probed at the nanoscale and in the same area, to identify the ionic processes occurring inside each individual layer and understand the impact on the entire battery cell...
2018: Beilstein Journal of Nanotechnology
Sašo Gyergyek, David Pahovnik, Ema Žagar, Alenka Mertelj, Rok Kostanjšek, Miloš Beković, Marko Jagodič, Heinrich Hofmann, Darko Makovec
Nanocomposites with a high, uniform loading of magnetic nanoparticles are very desirable for applications such as electromagnetic shielding and cancer treatment based on magnetically induced hyperthermia. In this study, a simple and scalable route for preparing nanocomposites with a high, uniform loading of magnetic nanoparticles is presented. The magnetic iron-oxide nanoparticles were functionalized with a methacrylate-based monomer that copolymerized in a toluene solution with the methyl methacrylate (MMA) monomer...
2018: Beilstein Journal of Nanotechnology
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