Search Results

Now showing 1 - 10 of 862
  • Item
    Engineering new limits to magnetostriction through metastability in iron-gallium alloys
    ([London] : Nature Publishing Group UK, 2021) Meisenheimer, P.B.; Steinhardt, R.A.; Sung, S.H.; Williams, L.D.; Zhuang, S.; Nowakowski, M.E.; Novakov, S.; Torunbalci, M.M.; Prasad, B.; Zollner, C. J.; Wang, Z.; Dawley, N.M.; Schubert, J.; Hunter, A.H.; Manipatruni, S.; Nikonov, D.E.; Young, I.A.; Chen, L.Q.; Bokor, J.; Bhave, S.A.; Ramesh, R.; Hu, J.-M.; Kioupakis, E.; Hovden, R.; Schlom, D.G.; Heron, J.T.
    Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare-earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. Fe1−xGax alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC Fe1−xGax alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A Fe1−xGax − [Pb(Mg1/3Nb2/3)O3]0.7−[PbTiO3]0.3 (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10−5 s m−1. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.
  • Item
    Electron-to Hole Transport Change Induced by Solvent Vapor Annealing of Naphthalene Diimide Doped with Poly(3-Hexylthiophene)
    (Lausanne : Frontiers Media, 2021) Janus, Krzysztof; Danielewicz, Kinga; Chlebosz, Dorota; Goldeman, Waldemar; Kiersnowski, Adam
    Herein we report on fabrication and properties of organic field-effect transistors (OFETs) based on the spray-coated films of N,N′-dioctyl naphthalene diimide (NDIC8) doped with 2.4 wt% of poly (3-hexylthiophene) (P3HT). OFETs with the untreated NDIC8:P3HT films revealed electron conductivity [μe* = 5 × 10–4 cm2×(Vs)−1]. After the annealing in chloroform vapor the NDIC8:P3HT films revealed the hole transport only [μh* = 0.9 × 10–4 cm2×(Vs)−1]. Due to the chemical nature and energy levels, the hole transport was not expected for NDIC8-based system. Polarized optical- and scanning electron microscopies indicated that the solvent vapor annealing of the NDIC8:P3HT films caused a transition of their fine-grained morphology to the network of branched, dendritic crystallites. Grazing incidence wide-angle X-ray scattering studies indicated that the above transition was accompanied by a change in the crystal structure of NDIC8. The isotropic crystal structure of NDIC8 in the untreated film was identical to the known crystal structure of the bulk NDIC8. After the solvent annealing the crystal structure of NDIC8 changed to a not-yet-reported polymorph, that, unlike in the untreated film, was partially oriented with respect to the OFET substrate.
  • Item
    Membrane Functionalization in Pilot Scale: Roll‐to‐Roll Electron Beam System with Inline Contact Angle Determination
    (Weinheim : Wiley-VCH, 2021) Schulze, Agnes; Drößler, Lutz; Weiß, Steffen; Went, Marco; Abdul Latif, Amira; Breite, Daniel; Fischer, Kristina
    To increase the permeation performance and antifouling properties of polymer membranes, a one-step reaction using electron irradiation was developed. This process combines the surface activation of the membrane polymer and the simultaneous permanent immobilization of hydrophilic molecules. This technology can be applied to various polymers, flat sheet/hollow fiber membranes and all pore ranges. The roll-to-roll system developed for this enables all process steps including inline analysis for quality control of the membrane surface in a continuously operated system. © 2021 The Authors. Chemie Ingenieur Technik published by Wiley-VCH GmbH
  • Item
    Enlightening Materials with Photoswitches
    (Weinheim : Wiley-VCH, 2020) Goulet-Hanssens, Alexis; Eisenreich, Fabian; Hecht, Stefan
    Incorporating molecular photoswitches into various materials provides unique opportunities for controlling their properties and functions with high spatiotemporal resolution using remote optical stimuli. The great and largely still untapped potential of these photoresponsive systems has not yet been fully exploited due to the fundamental challenges in harnessing geometrical and electronic changes on the molecular level to modulate macroscopic and bulk material properties. Herein, progress made during the past decade in the field of photoswitchable materials is highlighted. After pointing to some general design principles, materials with an increasing order of the integrated photoswitchable units are discussed, spanning the range from amorphous settings over surfaces/interfaces and supramolecular ensembles, to liquid crystalline and crystalline phases. Finally, some potential future directions are pointed out in the conclusion. In view of the exciting recent achievements in the field, the future emergence and further development of light-driven and optically programmable (inter)active materials and systems are eagerly anticipated. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
  • Item
    Mechanochemical activation of disulfide-based multifunctional polymers for theranostic drug release
    (Cambridge : RSC, 2021) Shi, Zhiyuan; Song, Qingchuan; Göstl, Robert; Herrmann, Andreas
    Drug delivery systems responsive to physicochemical stimuli allow spatiotemporal control over drug activity to overcome limitations of systemic drug administration. Alongside, the non-invasive real-time tracking of drug release and uptake remains challenging as pharmacophore and reporter function are rarely unified within one molecule. Here, we present an ultrasound-responsive release system based on the mechanochemically induced 5-exo-trigcyclization upon scission of disulfides bearing cargo molecules attachedviaβ-carbonate linker within the center of a water soluble polymer. In this bifunctional theranostic approach, we release one reporter molecule per drug molecule to quantitatively track drug release and distribution within the cell in real-time. We useN-butyl-4-hydroxy-1,8-naphthalimide and umbelliferone as fluorescent reporter molecules to accompany the release of camptothecin and gemcitabine as clinically employed anticancer agents. The generality of this approach paves the way for the theranostic release of a variety of probes and drugs by ultrasound. © The Royal Society of Chemistry 2020.
  • Item
    ConsensusPrime—A Bioinformatic Pipeline for Ideal Consensus Primer Design
    (Basel : MDPI, 2022) Collatz, Maximilian; Braun, Sascha D.; Monecke, Stefan; Ehricht, Ralf
    Background: High-quality oligonucleotides for molecular amplification and detection procedures of diverse target sequences depend on sequence homology. Processing input sequences and identifying homogeneous regions in alignments can be carried out by hand only if they are small and contain sequences of high similarity. Finding the best regions for large and inhomogeneous alignments needs to be automated. Results: The ConsensusPrime pipeline was developed to sort out redundant and technical interfering data in multiple sequence alignments and detect the most homologous regions from multiple sequences. It automates the prediction of optimal consensus primers for molecular analytical and sequence-based procedures/assays. Conclusion: ConsensusPrime is a fast and easy-to-use pipeline for predicting optimal consensus primers that is executable on local systems without depending on external resources and web services. An implementation in a Docker image ensures platform-independent executability and installability despite the combination of multiple programs. The source code and installation instructions are publicly available on GitHub.
  • Item
    Effect of Stacking Fault Energy on Microstructure and Texture Evolution during the Rolling of Non-Equiatomic CrMnFeCoNi High-Entropy Alloys
    (Basel : MDPI, 2020) Dan Sathiaraj, G.; Kalsar, Rajib; Suwas, Satyam; Skrotzki, Werner
    The evolution of microstructure and texture in three non-equiatomic CrMnFeCoNi high-entropy alloys (HEAs) with varying stacking fault energy (SFE) has been studied in up to 90% rolling reductions at both room and cryogenic temperature. All the HEAs deform by dislocation slip and additional mechanical twinning at intermediate and shear banding at high rolling strains. The microstructure is quite heterogeneous and, with strain, becomes highly fragmented. During rolling, a characteristic brass-type texture develops. Its strength increases with a decreasing SFE and the lowering of the rolling temperature. The texture evolution is discussed with regard to planar slip, mechanical twinning, and shear banding. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  • Item
    A Holistic Solution to Icing by Acoustic Waves: De-Icing, Active Anti-Icing, Sensing with Piezoelectric Crystals, and Synergy with Thin Film Passive Anti-Icing Solutions
    (Weinheim : Wiley-VCH, 2023) del Moral, Jaime; Montes, Laura; Rico‐Gavira, Victor Joaquin; López‐Santos, Carmen; Jacob, Stefan; Oliva‐Ramirez, Manuel; Gil‐Rostra, Jorge; Fakhfouri, Armaghan; Pandey, Shilpi; Gonzalez del Val, Miguel; Mora, Julio; García‐Gallego, Paloma; Ibáñez‐Ibáñez, Pablo Francisco; Rodríguez‐Valverde, Miguel Angel; Winkler, Andreas; Borrás, Ana; González‐Elipe, Agustin Rodriguez
    Icing has become a hot topic both in academia and in the industry given its implications in transport, wind turbines, photovoltaics, and telecommunications. Recently proposed de-icing solutions involving the propagation of acoustic waves (AWs) at suitable substrates may open the path for a sustainable alternative to standard de-icing or anti-icing procedures. Herein, the fundamental interactions are unraveled that contribute to the de-icing and/or hinder the icing on AW-activated substrates. The response toward icing of a reliable model system consisting of a piezoelectric plate activated by extended electrodes is characterized at a laboratory scale and in an icing wind tunnel under realistic conditions. Experiments show that surface modification with anti-icing functionalities provides a synergistic response when activated with AWs. A thoughtful analysis of the resonance frequency dependence on experimental variables such as temperature, ice formation, or wind velocity demonstrates the application of AW devices for real-time monitoring of icing processes.
  • Item
    Molecularly Engineered Black Phosphorus Heterostructures with Improved Ambient Stability and Enhanced Charge Carrier Mobility
    (Weinheim : Wiley-VCH, 2021) Shi, Huanhuan; Fu, Shuai; Liu, Yannan; Neumann, Christof; Wang, Mingchao; Dong, Haiyun; Kot, Piotr; Bonn, Mischa; Wang, Hai I.; Turchanin, Andrey; Schmidt, Oliver G.; Shaygan Nia, Ali; Yang, Sheng; Feng, Xinliang
    Overcoming the intrinsic instability and preserving unique electronic properties are key challenges for the practical applications of black phosphorus (BP) under ambient conditions. Here, it is demonstrated that molecular heterostructures of BP and hexaazatriphenylene derivatives (BP/HATs) enable improved environmental stability and charge transport properties. The strong interfacial coupling and charge transfer between the HATs and the BP lattice decrease the surface electron density and protect BP sheets from oxidation, resulting in an excellent ambient lifetime of up to 21 d. Importantly, HATs increase the charge scattering time of BP, contributing to an improved carrier mobility of 97 cm2 V-1 s-1 , almost three times of the pristine BP films, based on noninvasive THz spectroscopic studies. The film mobility is an order of magnitude larger than previously reported values in exfoliated 2D materials. The strategy opens up new avenues for versatile applications of BP sheets and provides an effective method for tuning the physicochemical properties of other air-sensitive 2D semiconductors.
  • Item
    Substrate-Independent Magnetic Bistability in Monolayers of the Single-Molecule Magnet Dy2ScN@C80 on Metals and Insulators
    (Weinheim : Wiley-VCH, 2020) Krylov, Denis S.; Schimmel, Sebastian; Dubrovin, Vasilii; Liu, Fupin; Nguyen, T.T. Nhung; Spree, Lukas; Chen, Chia-Hsiang; Velkos, Georgios; Bulbucan, Claudiu; Westerström, Rasmus; Studniarek, Michał; Dreiser, Jan; Hess, Christian; Büchner, Bernd; Avdoshenko, Stanislav M.; Popov, Alexey A.
    Magnetic hysteresis is demonstrated for monolayers of the single-molecule magnet (SMM) Dy2ScN@C80 deposited on Au(111), Ag(100), and MgO|Ag(100) surfaces by vacuum sublimation. The topography and electronic structure of Dy2ScN@C80 adsorbed on Au(111) were studied by STM. X-ray magnetic CD studies show that the Dy2ScN@C80 monolayers exhibit similarly broad magnetic hysteresis independent on the substrate used, but the orientation of the Dy2ScN cluster depends strongly on the surface. DFT calculations show that the extent of the electronic interaction of the fullerene molecules with the surface is increasing dramatically from MgO to Au(111) and Ag(100). However, the charge redistribution at the fullerene-surface interface is fully absorbed by the carbon cage, leaving the state of the endohedral cluster intact. This Faraday cage effect of the fullerene preserves the magnetic bistability of fullerene-SMMs on conducting substrates and facilitates their application in molecular spintronics. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.