jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Madani Labed | Nouredine Sengouga | You Seung Rim
Source: Nanomaterials (article, 2022-03-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Control of Ni/β-Ga2O3 Vertical Schottky Diode Output Parameters at Forward Bias by Insertion of a Graphene Layer Controlling the Schottky barrier height (ϕB) and other parameters of Schottky barrier diodes (SBD) is critical for many applications. In this work, the effect of inserting a graphene interfacial monolayer between a Ni Schottky metal and a β-Ga2O3 semiconductor was investigated using numerical simulation. We confirmed that the simulation-based on Ni workfunction, interfacial trap concentration, and surface electron affinity was well-matched with the actual device characterization. Insertion of the graphene layer achieved a remarkable decrease in the barrier height (ϕB), from 1.32 to 0.43 eV, and in the series resistance (RS), from 60.3 to 2.90 mΩ.cm2. However, the saturation current (JS) increased from 1.26×10−11 to 8.3×10−7(A/cm2). The effects of a graphene bandgap and workfunction were studied. With an increase in the graphene workfunction and bandgap, the Schottky barrier height and series resistance increased and the saturation current decreased. This behavior was related to the tunneling rate variations in the graphene layer. Therefore, control of Schottky barrier diode output parameters was achieved by monitoring the tunneling rate in the graphene layer (through the control of the bandgap) and by controlling the Schottky barrier height according to the Schottky−Mott role (through the control of the workfunction). Furthermore, a zero-bandgap and low-workfunction graphene layer behaves as an ohmic contact, which is in agreement with published results. Graphene ; Materials science ; Schottky diode ; Layer (electronics) ; Optoelectronics ; Diode ; Schottky barrier ; Nanotechnology Ga2O3 and related materials ; ZnO doping and properties ; Advanced Photocatalysis Techniques
Authors: Thomas Fix | Jean‐Luc Rehspringer | Stéphane Roques | A. Slaoui
Source: Emergent Materials (article, 2022-08-24)
Field: Materials Science — Materials Chemistry

Preparation of β-CuGaO2 thin films by ion-exchange of β-NaGaO2 film fabricated by a solgel method Materials science ; Thin film ; Band gap ; Optoelectronics ; Dopant ; Wafer ; Wurtzite crystal structure ; Spin coating ; Surface photovoltage ; Doping ; Nanotechnology ; Spectroscopy ZnO doping and properties ; Copper-based nanomaterials and applications ; Ga2O3 and related materials
Authors: Xiaolong Song | Xiaoya Yan | Na Li | Lin Shen | Mingli Wang
Source: Coatings (article, 2022-10-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Study on the Performance of Ag-Cu Bimetal SERS Substrate SERS has become a powerful trace detection technology, but its practical application is often limited by the fixed optical properties of cast metals (Au, Ag and Cu). In this paper, the bimetallic nanostructures prepared by changing the metal content ratio can regulate the different optical responses of the substrate. In addition, it was found that the scale of moth wings (MW) with 3D grating-like uniform nanoarrays using bioscaffold can provide a consistently high-density ‘hot spot’ for the as-prepared plasmonic substrate. Here, two different methods (i) co-sputtered with different times and (ii) sputtered with sequentially alternating to form a stratified structure on the MW were employed for the fabrication of SERS-active substrates, and they were named AgCu@MW and Ag@Cu@MW, respectively. The comparison SERS measurement results of the above two substrates by using probe molecules R6G and MB show that the stratified structure of the Ag@Cu@MW-3 substrate has higher SERS performance. This strategy can not only prepare plasma substrates with on-demand optical responses but also provide new ideas for the preparation of conventional biomimetic nanomaterials. Bimetal ; Bimetallic strip ; Substrate (aquarium) ; Materials science ; Plasmon ; Nanotechnology ; Nanomaterials ; Fabrication ; Nanostructure ; Metal ; Optoelectronics ; Chemical engineering ; Metallurgy Gold and Silver Nanoparticles Synthesis and Applications ; Near-Field Optical Microscopy ; Plasmonic and Surface Plasmon Research
Authors: Eva De Leo | Aurelio A. Rossinelli | Patricia Marqués‐Gallego | Lisa V. Poulikakos | David J. Norris | Ferry Prins
Source: Nanoscale (article, 2022-01-01)
Field: Materials Science — Materials Chemistry

Polarization-based colour tuning of mixed colloidal quantum-dot thin films using direct patterning Colloidal quantum-dots (cQDs) are finding increasingly widespread application in photonics and optoelectronics, providing high brightness and record-wide colour gamuts. However, the external quantum efficiencies in thin-film device architectures are still limited due to losses into waveguide modes and different strategies are being explored to promote the outcoupling of emission. Here we use a template-stripping-based direct-patterning strategy to fabricate linear gratings at the surface of cQD thin films. The linear gratings enhance optical outcoupling through Bragg scattering, yielding bright emission with a strong degree of linear polarization. By patterning linear gratings with different periodicities and orientations onto a film of mixed-colour cQDs, we demonstrate polarization-based active colour tuning of the thin-film emission. Quantum dot ; Materials science ; Polarization (electrochemistry) ; Colloid ; Nanotechnology ; Thin film ; Optoelectronics ; Chemistry ; Chemical engineering ; Engineering Quantum Dots Synthesis And Properties ; Photonic Crystals and Applications ; Near-Field Optical Microscopy
Authors: Jiahui Jia | Xu He | Arsalan Akhtar | G. Herranz | Miguel Pruneda
Source: Physical review. B./Physical review. B (article, 2022-06-23)
Field: Materials Science — Materials Chemistry

Dynamic control of octahedral rotation in perovskites by defect engineering Engineering oxygen octahedra rotation patterns in $AB{\text{O}}_{3}$ perovskites is a powerful route to design functional materials. Here we propose a strategy that exploits point defects that create local electric dipoles and couple to the oxygen sublattice, enabling direct actuation on the rotational degrees of freedom. This approach, which relies on substituting an $A$ site with a smaller ion, paves a way to couple dynamically octahedra rotations to external electric fields. A common antisite defect, ${\mathrm{Al}}_{\mathrm{La}}$, in rhombohedral ${\mathrm{LaAlO}}_{3}$ is taken as a prototype to validate the idea, with atomistic density functional theory calculations supported with an effective lattice model to simulate the dynamics of switching of the local rotational degrees of freedom to long distances. Our simulations provide an insight of the main parameters that govern the operation of the proposed mechanism, and allow to define guidelines for screening other systems where this approach could be used for tuning the properties of the host material. Octahedron ; Dipole ; Degrees of freedom (physics and chemistry) ; Rotation (mathematics) ; Lattice (music) ; Density functional theory ; Materials science ; Condensed matter physics ; Chemical physics ; Physics ; Computer science ; Crystallography ; Crystal structure ; Chemistry ; Quantum mechanics Electronic and Structural Properties of Oxides ; Magnetic and transport properties of perovskites and related materials ; Ferroelectric and Piezoelectric Materials
Authors: Péter Adler | Liane Schröder | K. Teske | M. Reehuis | A. Hoser | Patrick Merz | Walter Schnelle | Claudia Felser | Martin Jansen
Source: Physical Chemistry Chemical Physics (article, 2022-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Oxygen deficiency in Sr<sub>2</sub>FeO<sub>4−<i>x</i></sub>: electrochemical control and impact on magnetic properties The oxygen-deficient system Sr<sub>2</sub>FeO<sub>4-<i>x</i></sub> was explored by heating the stoichiometric Fe<sup>4+</sup> oxide Sr<sub>2</sub>FeO<sub>4</sub> in well-defined oxygen partial pressures which were controlled electrochemically by solid-state electrolyte coulometry. Samples with <i>x</i> up to about 0.2 were obtained by this route. X-ray diffraction analysis reveals that the K<sub>2</sub>NiF<sub>4</sub>-type crystal structure (space group <i>I</i>4/<i>mmm</i>) of the parent compound is retained. The lattice parameter <i>a</i> slightly decreases while the <i>c</i>-parameter increases with increasing <i>x</i>, which is in contrast to the Ruddlesden-Popper system Sr<sub>3</sub>Fe<sub>2</sub>O<sub>7-<i>x</i></sub> and suggests removal of oxygen atoms from FeO<sub>2</sub> lattice planes. The magnetic properties were studied by magnetization, <sup>57</sup>Fe Mössbauer, and powder neutron diffraction experiments. The results suggest that extraction of oxygen atoms from the lattice progressively changes the elliptical spiral spin ordering of the parent compound to an inhomogeneous magnetic state with coexistence of long-range ordered regions adopting a circular spin spiral and smaller magnetic clusters. Electrochemistry ; Magnetism ; Oxygen ; Oxygen deficiency ; Oxide ; Materials science ; Inorganic chemistry ; Oxygen evolution ; Chemistry ; Analytical Chemistry (journal) ; Physical chemistry ; Condensed matter physics ; Metallurgy ; Physics ; Electrode Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics ; Multiferroics and related materials
Authors: Amy Witzmann | Calum K. Gordon | Jesse Howarth | Sophie Unsworth | Aurélien Rossi | Jake Hardy | Michael B. Price | Nathaniel J. L. K. Davis
Source: Luminescence (article, 2022-11-26)
Field: Chemistry — Physical and Theoretical Chemistry

Luminescent light diffuser for diffuse lighting applications The lighting industry currently accounts for a significant proportion of all energy demand. Luminescent white lighting is often impure, inefficient, expensive, and detrimentally emits as a point source, meaning the light is emitted from a focused point. A luminescent light diffuser offers the potential to create a spatially broad lighting fixture. We developed a luminescent light diffuser consisting of three commercially available luminescent dye species (rhodamine 6G, fluorescein, 7-diethylamino-4-methylcoumarin) dispersed within a polymer matrix (polyvinyl alcohol), or commercial paint, and coated on a planar waveguide. A Light-emitting diode (LED) (385 nm) is directed into the waveguide which excites the luminescent species, coating the panel, creating a device that emits spatially broad pure white light. As the emission depends on escape cone emission from the waveguide, the device's emission was found to depend highly on the coating film quality and components. We present two systems: a small 40 mm × 40 mm prototype, made using standard water-soluble polymer (polyvinyl alcohol), to study the underlying operational principles, and a 100 mm <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>×</mml:mo></mml:math> 100 mm device with optimized efficiency fabricated with a clear commercial paint. By doping the polymer matrix with scattering silica microparticles we achieved a maximum photon outcoupling efficiency of 78%, whilst maintaining colour purity with an increased device size of more than 300 times (compared with the input LED). This work shows that it is possible to construct an inexpensive and spatially broad lighting source, whilst maintaining colour purity at a low cost. Diffuser (optics) ; Luminescence ; Materials science ; Polyvinyl alcohol ; Optoelectronics ; Light-emitting diode ; Optics ; Rhodamine 6G ; Coating ; Polymer ; Phosphor ; Nanotechnology ; Light source ; Composite material ; Fluorescence Photochemistry and Electron Transfer Studies ; Photonic Crystals and Applications ; Organic Light-Emitting Diodes Research
Authors: Sourav Dey | Gopalan Rajaraman | Hélène Bolvin
Source: Chemistry - A European Journal (article, 2022-08-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Analysis of the Magnetic Coupling in a Mn(II)‐U(V)‐Mn(II) Single Molecule Magnet [{Mn(TPA)I}{UO2(Mesaldien)}{Mn(TPA)I}]I formula (here TPA=tris(2-pyridylmethyl)amine and Mesaldien=N,N'-(2-aminomethyl)diethylenebis(salicylidene imine)) reported by Mazzanti and coworkers (Chatelain et al. Angew. Chem. Int. Ed. 2014, 53, 13434) is so far the best Single Molecule Magnet (SMM) in the {3d-5f} class of molecules exhibiting barrier height of magnetization reversal as high as 81.0 K. In this work, we have employed a combination of ab initio CAS and DFT methods to fully characterize this compound and to extract the relevant spin Hamiltonian parameters. We show that the signs of the magnetic coupling and of the g-factors of the monomers are interconnected. The central magnetic unit [U<sup>V</sup> O<sub>2</sub> ]<sup>+</sup> is described by a Kramers Doublet (KD) with negative g-factors, due to a large orbital contribution. The magnetic coupling for the {Mn(II)-U(V)} pair is modeled by an anisotropic exchange Hamiltonian: all components are ferromagnetic in terms of spin moments, the parallel component J<sub>Z</sub> twice larger as the perpendicular one J<sub>⊥</sub> . The spin density distribution suggests that spin polarization on the U(V) center favors the ferromagnetic coupling. Further, the J<sub>Z</sub> /J<sub>⊥</sub> ratio, which is related to the barrier height, was found to correlate to the corresponding spin contribution of the g-factors of the U(V) center. This correlation established for the first time offers a direct way to estimate this important ratio from the corresponding g<sup>S</sup> -values, which can be obtained using traditional ab initio packages and hence has a wider application to other {3d-5f} magnets. It is finally shown that the magnetization barrier height is tuned by the splitting of the [U<sup>V</sup> O<sub>2</sub> ]<sup>+</sup> 5 f orbitals. Ferromagnetism ; Magnetization ; Chemistry ; Ab initio ; Magnetic moment ; Ab initio quantum chemistry methods ; Single-molecule magnet ; Magnetic anisotropy ; Condensed matter physics ; Density functional theory ; Molecule ; Spin polarization ; Crystallography ; Molecular physics ; Computational chemistry ; Magnetic field ; Physics ; Electron Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Metal-Catalyzed Oxygenation Mechanisms
Authors: Minh‐Duc Hoang | Farah Savina | Philippe Durand | Rachel Méallet‐Renault | Gilles Clavier | Arnaud Chevalier
Source: ChemPhotoChem (article, 2022-08-19)
Field: Chemistry — Spectroscopy

Tunable Naphthalimide/Cinnoline‐Fused (CinNapht) Hybrid Dyes for Fluorescence Imaging in Living Cells Abstract This paper presents the synthesis, photophysical characterization and use for cell imaging of 14 fluorophores derived from a hybrid Naphthalimide/Cinnoline fused backbone called “CinNapht”. Photophysical properties of these fluorophores including absorbance, excitation and emission spectra have been recorded in CHCl 3 , DMSO and PBS+5 %BSA. They exhibit red emission associated to a large Stokes shift and fluorescence quantum yields up to 52 %. Theoretical calculations have been undertaken in order to provide elements of rationalization for a major part of the results. Some of these analogues have been tuned to enable imaging of cell organelles such as mitochondria, lysosome or lipid droplets. This study comes to confirm that CinNapht dyes can be considered as relevant alternatives to existing tools for cell imaging. Cinnoline ; Fluorescence ; Stokes shift ; Photochemistry ; Organelle ; Chemistry ; BODIPY ; Absorbance ; Nanotechnology ; Materials science ; Organic chemistry ; Optics ; Physics ; Chromatography ; Biochemistry Molecular Sensors and Ion Detection ; Luminescence and Fluorescent Materials ; Lanthanide and Transition Metal Complexes
Authors: Uyen Tu Lieu | Natsuhiko Yoshinaga
Source: Soft Matter (article, 2022-01-01)
Field: Materials Science — Materials Chemistry

Formation and fluctuation of two-dimensional dodecagonal quasicrystals The self-assembly of two-dimensional dodecagonal quasicrystals (DDQCs) from patchy particles is investigated by Brownian dynamics simulations. The patchy particle has a five-fold rotational symmetry pattern described by the spherical harmonics <i>Y</i><sub>55</sub>. From the formation of the DDQC obtained by an annealing process, we find the following mechanism. The early stage of the dynamics is dominated by hexagonal structures. Then, nucleation of dodecagonal motifs appears by particle rearrangement, and finally the motifs span the whole system. The transition from the hexagonal structure into the dodecagonal motif is coincident with the collective motion of the particles. The DDQC consists of clusters of dodecagonal motifs, which can be classified into several packing structures. By the analyses of the DDQC under fixed temperature, we find that the fluctuations are characterised by changes in the network of the dodecagonal motifs. Finally we compare the DDQCs assembled from the patchy particle system and isotropic particle system. The two systems share a similar mechanism of the formation and fluctuation of DDQCs. Quasicrystal ; Isotropy ; Nucleation ; Condensed matter physics ; Brownian dynamics ; Crystallography ; Particle (ecology) ; Chemical physics ; Harmonics ; Brownian motion ; Materials science ; Physics ; Optics ; Chemistry ; Thermodynamics Quasicrystal Structures and Properties ; Mineralogy and Gemology Studies ; Photonic Crystals and Applications
Authors: Areg Ghazaryan | Ammar Kirmani | Rafael M. Fernandes | Pouyan Ghaemi
Source: Physical review. B./Physical review. B (article, 2022-11-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Anomalous Shiba states in topological iron-based superconductors We demonstrate the formation of robust zero-energy modes close to magnetic impurities in the iron-based superconductor ${\mathrm{FeSe}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$. We find that the Zeeman field generated by the impurity favors a spin-triplet interorbital pairing as opposed to the spin-singlet intraorbital pairing prevalent in the bulk. The preferred spin-triplet pairing preserves time-reversal symmetry and is topological, as robust, topologically protected zero modes emerge at the boundary between regions with different pairing states. Moreover, the zero modes form Kramers doublets that are insensitive to the direction of the spin polarization or to the separation between impurities. We argue that our theoretical results are consistent with recent experimental measurements on ${\mathrm{FeSe}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$. Pairing ; Zeeman effect ; Physics ; Condensed matter physics ; Superconductivity ; Impurity ; Singlet state ; Spin (aerodynamics) ; Zero-point energy ; Point reflection ; Zero (linguistics) ; Symmetry (geometry) ; Magnetic field ; Quantum mechanics ; Excited state Iron-based superconductors research ; Topological Materials and Phenomena ; Advanced Condensed Matter Physics
Authors: Serik Akhmediev | Valentin Mikhailov | Gulzada Tazhenova | Madi Bakirov | Tatiana F. Filippova | Daniyar Tokanov
Source: Istrazivanja i projektovanja za privredu (article, 2022-11-30)
Field: Materials Science — Materials Chemistry

Calculating a beam of variable section lying on an elastic foundation In this article, there has been studied the bending state of a reinforced concrete beam with a variable cross-sectional height along its length that rests along its entire length on a brick wall. The beam is under the action of arbitrarily located concentrated forces. The study has been performed on the basis of the original inhomogeneous differential equation of the 4th order, taking into account the external load and the bedding coefficients of the elastic foundation. Using the finite difference method, typical resolving finite difference equations have been obtained. A study of the influence of the degree of elasticity of the base, with a change in the value of the bed coefficients and elasticity parameters, was conducted. The results confirm the reliability of theoretical and practical calculations. Given theoretical provisions and applied results can be used in scientific research in the field of mechanics of a deformable solid body, as well as in practical design. Elasticity (physics) ; Beam (structure) ; Structural engineering ; Finite element method ; Differential equation ; Finite difference ; Deflection (physics) ; Mechanics ; Mathematics ; Mathematical analysis ; Physics ; Classical mechanics ; Engineering Structural mechanics and materials ; Engineering and Agricultural Innovations ; Composite Structure Analysis and Optimization
Authors: Jinbing Cheng | Junbao He | Chunying Pu | Congbin Liu | Xiaoyu Huang | Deyang Zhang | Hailong Yan | Paul K. Chu
Source: Energies (article, 2022-08-25)
Field: Materials Science — Materials Chemistry

MoS2 Transistors with Low Schottky Barrier Contact by Optimizing the Interfacial Layer Thickness Molybdenum disulfide (MoS2) has attracted great attention from researchers because of its large band gap, good mechanical toughness and stable physical properties; it has become the ideal material for the next-generation optoelectronic devices. However, the large Schottky barrier height (ΦB) and contact resistance are obstacles hampering the fabrication of high-power MoS2 transistors. The electronic transport characteristics of MoS2 transistors with two different contact structures are investigated in detail, including a copper (Cu) metal–MoS2 channel and copper (Cu) metal–TiO2-MoS2 channel. Contact optimization is conducted by adjusting the thickness of the TiO2 interlayer between the metal and MoS2. The metal-interlayer-semiconductor (MIS) structure with a 1.5 nm thick TiO2 layer has a smaller Schottky barrier of 22 meV. The results provide insights into the engineering of MIS contacts and interfaces to improve transistor characteristics. Schottky barrier ; Materials science ; Contact resistance ; Transistor ; Optoelectronics ; Layer (electronics) ; Fabrication ; Molybdenum disulfide ; Semiconductor ; Copper ; Nanotechnology ; Composite material ; Electrical engineering ; Metallurgy ; Voltage 2D Materials and Applications ; MXene and MAX Phase Materials ; Semiconductor materials and interfaces
Authors: Monika Vogler | Jonas Busk | Hamidreza Hajiyani | Peter Bjørn Jørgensen | Nehzat Safaei | Ivano E. Castelli | Francisco Ramirez | Johan M. Carlsson | Giovanni Pizzi | Simon Clark | Felix Hanke | Arghya Bhowmik | Helge S. Stein
Source: ChemRxiv (preprint, 2022-09-06)
Field: Materials Science — Materials Chemistry

Brokering between tenants for an international materials acceleration platform The future of materials science is borderless, cooperative, and distributed across the globe. This necessitates flexible, reconfigurable software defined research workflows, which we herein demonstrate by integrating multiple disciplines and modalities. Our brokering approach to research orchestration exposes entire laboratories in a cooperative multi-tenancy platform that is asynchronous, modular, and resilient. To the best of our knowledge, this constitutes the first international materials acceleration platform (MAP) which is herein demonstrated through a battery electrolyte workflow that ran in five countries over two weeks. We discuss the lessons learned from multi-tenancy and fault tolerance and chart a way to a universal battery MAP with fully ontology- based schemas and cost-aware orchestration. Workflow ; Orchestration ; Computer science ; Modular design ; Asynchronous communication ; Software engineering ; Ontology ; Software ; Debugging ; World Wide Web ; Distributed computing ; Operating system ; Database ; Computer network Machine Learning in Materials Science ; Innovative Microfluidic and Catalytic Techniques Innovation ; Scientific Computing and Data Management