jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ritesh Haldar | Marius Jakoby | Antoine Mazel | Qiang Zhang | Alexander Welle | Tawheed Mohamed | Peter Krolla | Wolfgang Wenzel | Stéphane Diring | Fabrice Odobel | Bryce S. Richards | Ian A. Howard | Christof Wöll
Source: Nature Communications (article, 2018-10-12)
Field: Materials Science — Materials Chemistry

Anisotropic energy transfer in crystalline chromophore assemblies An ideal material for photon harvesting must allow control of the exciton diffusion length and directionality. This is necessary in order to guide excitons to a reaction center, where their energy can drive a desired process. To reach this goal both of the following are required; short- and long-range structural order in the material and a detailed understanding of the excitonic transport. Here we present a strategy to realize crystalline chromophore assemblies with bespoke architecture. We demonstrate this approach by assembling anthracene dibenzoic acid chromophore into a highly anisotropic, crystalline structure using a layer-by-layer process. We observe two different types of photoexcited states; one monomer-related, the other excimer-related. By incorporating energy-accepting chromophores in this crystalline assembly at different positions, we demonstrate the highly anisotropic motion of the excimer-related state along the [010] direction of the chromophore assembly. In contrast, this anisotropic effect is inefficient for the monomer-related excited state. Chromophore ; Exciton ; Materials science ; Excited state ; Excimer ; Anisotropy ; Chemical physics ; Monomer ; Anthracene ; Optoelectronics ; Photochemistry ; Nanotechnology ; Molecular physics ; Polymer ; Optics ; Chemistry ; Fluorescence ; Atomic physics ; Physics ; Condensed matter physics Luminescence and Fluorescent Materials ; Spectroscopy and Quantum Chemical Studies ; Perovskite Materials and Applications
Authors: Ranjana Aggarwal | Suresh Kumar
Source: Beilstein Journal of Organic Chemistry (review, 2018-01-25)
Field: Chemistry — Organic Chemistry

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines The condensation of 5-aminopyrazole with various bielectrophilic moieties results in the formation of pyrazoloazines, an interesting array of fused heterocyclic systems. The development of new synthetic routes towards pyrazoloazines for their biological and medicinal exploration is an attractive area for researchers throughout the world. The present review focuses on various synthetic methods developed in the last decade for the synthesis of differently substituted pyrazoloazines by a broad range of organic reactions by means of 5-aminopyrazole as a precursor. Chemistry ; Combinatorial chemistry ; Condensation ; Organic synthesis ; Nanotechnology ; Organic chemistry ; Catalysis Synthesis and biological activity ; Synthesis and Biological Evaluation ; Multicomponent Synthesis of Heterocycles
Authors: Fei Liu | Shailja Goyal | Michael Forrester | Tao Ma | Kyle Miller | Yasmeen Mansoorieh | John Henjum | Lin Zhou | Eric W. Cochran | Shan Jiang
Source: Nano Letters (article, 2018-12-26)
Field: Materials Science — Materials Chemistry

Self-assembly of Janus Dumbbell Nanocrystals and Their Enhanced Surface Plasmon Resonance Self-assembly is a critical process that can greatly expand the existing structures and lead to new functionality of nanoparticle systems. Multicomponent superstructures self-assembled from nanocrystals have shown promise as multifunctional materials for various applications. Despite recent progress in assembly of homogeneous nanocrystals, synthesis and self-assembly of Janus nanocrystals with contrasting surface chemistry remains a significant challenge. Herein, we designed a novel Janus nanocrystal platform to control the self-assembly of nanoparticles in aqueous solutions by balancing the hydrophobic and hydrophilic moieties. A series of superstructures have been assembled by systematically varying the Janus balance and assembly conditions. Janus Au-Fe<sub>3</sub>O<sub>4</sub> dumbbell nanocrystals (<20 nm) were synthesized with the hydrophobic ligands coated on the Au lobe and negatively charged hydrophilic ligands coated on the Fe<sub>3</sub>O<sub>4</sub> lobe. We systematically fine-tune the lobe size ratio, surface coating, external conditions, and even additional growth of Au nanocrystal domains on the Au lobe of dumbbell nanoparticles (Au-Au-Fe<sub>3</sub>O<sub>4</sub>) to harvest self-assembly structures including clusters, chains, vesicles, and capsules. It was discovered that in all these assemblies the hydrophobic Au lobes preferred to stay together. In addition, these superstructures clearly demonstrated different levels of enhanced surface plasmon resonance that is directly correlated with the Au coupling in the assembly structure. The strong interparticle plasmonic coupling displayed a red-shift in surface plasmon resonance, with larger structures formed by Au-Au-Fe<sub>3</sub>O<sub>4</sub> assembly extending into the near-infrared region. Self-assembly of Janus dumbbell nanocrystals can also be reversible under different pH values. The biphasic Janus dumbbell nanocrystals offer a platform for studying the novel interparticle coupling and open up opportunities in applications including sensing, disease diagnoses, and therapy. Janus ; Surface plasmon resonance ; Dumbbell ; Nanocrystal ; Materials science ; Nanotechnology ; Resonance (particle physics) ; Plasmon ; Self-assembly ; Surface plasmon ; Nanoparticle ; Optoelectronics ; Physics ; Atomic physics Pickering emulsions and particle stabilization ; Gold and Silver Nanoparticles Synthesis and Applications ; Surfactants and Colloidal Systems
Authors: Stefano F. Pizzolato | Peter Štacko | Jos C. M. Kistemaker | Thomas Van Leeuwen | Edwin Otten | Ben L. Feringa
Source: Journal of the American Chemical Society (article, 2018-11-20)
Field: Chemistry — Organic Chemistry

Central-to-Helical-to-Axial-to-Central Transfer of Chirality with a Photoresponsive Catalyst Recent advances in molecular design have displayed striking examples of dynamic chirality transfer between various elements of chirality, e.g., from central to either helical or axial chirality and vice versa. While considerable progress in atroposelective synthesis has been made, it is intriguing to design chiral molecular switches able to provide selective and dynamic control of axial chirality with an external stimulus to modulate stereochemical functions. Here, we report the synthesis and characterization of a photoresponsive bis(2-phenol)-substituted molecular switch 1. The unique design exhibits a dynamic hybrid central-helical-axial transfer of chirality. The change of preferential axial chirality in the biaryl motif is coupled to the reversible switching of helicity of the overcrowded alkene core, dictated by the fixed stereogenic center. The potential for dynamic control of axial chirality was demonstrated by using ( R)-1 as switchable catalyst to direct the stereochemical outcome of the catalytic enantioselective addition of diethylzinc to aromatic aldehydes, with successful reversal of enantioselectivity for several substrates. Chirality (physics) ; Stereocenter ; Chemistry ; Axial chirality ; Enantioselective synthesis ; Helicity ; Stereochemistry ; Catalysis ; Planar chirality ; Organic chemistry ; Physics Axial and Atropisomeric Chirality Synthesis ; Molecular spectroscopy and chirality ; Synthesis and Properties of Aromatic Compounds
Authors: Guillaume Chastanet | Cédric Desplanches | Chérif Baldé | Patrick Rosa | Mathieu Marchivie | Philippe Guionneau
Source: Chemistry Squared (review, 2018-07-17)
Field: Materials Science — Electronic, Optical and Magnetic Materials

A critical review of the T(LIESST) temperature in spin crossover materials − What it is and what it is not Light-Induced Excited Spin-State Trapping has been studied since 1982 in solution and 1984 in solid state as it offers a reversible way of photoswitching the electronic configuration of spin crossover systems. Since then, the lifetime of the photo-induced state was deeply investigated through kinetics measurements. In 1998, a fast and easy way to record the limit temperature above which the photo-induced state is erased, denoted T(LIESST), was introduced. This procedure has been widely used in the spin crossover community due to its easiness and its efficiency to provide detailed information on the photo-induced state. Correlations between T(LIESST) and structural parameters have been proposed for instance. However, it intrinsically contains drawbacks that can lead to misinterpretation of behaviours and can lead to an over estimation of its scope. This review aims to present and discuss not only the correct way to measure T(LIESST) but also the essential contributions it has brought and the limits not to be exceeded in its interpretation. Spin crossover ; Spin states ; Crossover ; Condensed matter physics ; Excited state ; Chemistry ; Materials science ; Physics ; Nanotechnology ; Computer science ; Atomic physics Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: Berk Onat | Ekin D. Cubuk | Brad D. Malone | Efthimios Kaxiras
Source: Physical review. B./Physical review. B (article, 2018-03-20)
Field: Materials Science — Materials Chemistry

Implanted neural network potentials: Application to Li-Si alloys Modeling the behavior of materials composed of elements with different bonding and electronic structure character for large spatial and temporal scales and over a large compositional range is a challenging problem. Cases in point are amorphous alloys of Si, a prototypical covalent material, and Li, a prototypical metal, which are being considered as anodes for high-energy-density batteries. To address this challenge, we develop a methodology based on neural networks that extends the conventional training approach to incorporate pre-trained parts that capture the character of different components, into the overall network; we refer to this model as the ``implanted neural network'' method. We show that this approach works well for the Si-Li amorphous alloys for a wide range of compositions, giving good results for key quantities like the diffusion coefficients. The method is readily generalizable to more complicated situations that involve two or more different elements. Artificial neural network ; Character (mathematics) ; Amorphous solid ; Amorphous metal ; Materials science ; Computer science ; Range (aeronautics) ; Point (geometry) ; Diffusion ; Key (lock) ; Artificial intelligence ; Alloy ; Metallurgy ; Physics ; Chemistry ; Thermodynamics ; Mathematics ; Crystallography Machine Learning in Materials Science ; Advancements in Battery Materials ; Fuel Cells and Related Materials
Authors: Kyoungmin Min | Byung‐Jin Choi | Kwangjin Park | Eunseog Cho
Source: Scientific Reports (article, 2018-10-19)
Field: Materials Science — Materials Chemistry

Machine learning assisted optimization of electrochemical properties for Ni-rich cathode materials Optimizing synthesis parameters is the key to successfully design ideal Ni-rich cathode materials that satisfy principal electrochemical specifications. We herein implement machine learning algorithms using 330 experimental datasets, obtained from a controlled environment for reliability, to construct a predictive model. First, correlation values showed that the calcination temperature and the size of the particles are determining factors for achieving a long cycle life. Then, we compared the accuracy of seven different machine learning algorithms for predicting the initial capacity, capacity retention rate, and amount of residual Li. Remarkable predictive capability was obtained with the average value of coefficient of determinant, R<sup>2</sup> = 0.833, from the extremely randomized tree with adaptive boosting algorithm. Furthermore, we propose a reverse engineering framework to search for experimental parameters that satisfy the target electrochemical specification. The proposed results were validated by experiments. The current results demonstrate that machine learning has great potential to accelerate the optimization process for the commercialization of cathode materials. Computer science ; Boosting (machine learning) ; Algorithm ; Residual ; Machine learning ; Artificial intelligence Machine Learning in Materials Science ; Electron and X-Ray Spectroscopy Techniques ; Fuel Cells and Related Materials
Authors: Anirudh Raju Natarajan | Anton Van der Ven
Source: npj Computational Materials (article, 2018-10-26)
Field: Materials Science — Materials Chemistry

Machine-learning the configurational energy of multicomponent crystalline solids Abstract Machine learning tools such as neural networks and Gaussian process regression are increasingly being implemented in the development of atomistic potentials. Here, we develop a formalism to leverage such non-linear interpolation tools in describing properties dependent on occupation degrees of freedom in multicomponent solids. Symmetry-adapted cluster functions are used to differentiate distinct local orderings. These local features are used as input to neural networks that reproduce local properties such as the site energy. We apply the technique to reproduce a synthetic cluster expansion Hamiltonian with multi-body interactions, as well as the formation energies calculated from first-principles for the intercalation of lithium into TiS 2 . The formalism and results presented here show that complex multi-body interactions may be approximated by non-linear models involving smaller clusters. Artificial neural network ; Statistical physics ; Formalism (music) ; Leverage (statistics) ; Gaussian ; Hamiltonian (control theory) ; Energy landscape ; Cluster (spacecraft) ; Computer science ; Physics ; Biological system ; Artificial intelligence ; Mathematics ; Mathematical optimization ; Quantum mechanics ; Thermodynamics Machine Learning in Materials Science ; X-ray Diffraction in Crystallography ; Computational Drug Discovery Methods
Authors: Jude Chinedu Onwuka | E. B. Agbaji | V.O. Ajibola | Friday Godwin Okibe
Source: Applied Water Science (article, 2018-05-24)
Field: Materials Science — Surfaces, Coatings and Films

Treatment of crude oil-contaminated water with chemically modified natural fiber The dependence of Nigerian Government on foreign technology for oil spill cleanup in its water bodies does not add local content value in the development of the Nation’s economy. Acetylation of natural cellulose gives a material with high sorption capacity for oil in water. This research investigates crude oil sorption from water using acetylated and unacetylated lignocellulose. Oil palm empty fruit bunch (OPEFB) and cocoa pod (CP) were acetylated under mild conditions. The acetylated (modified) and unacetylated (unmodified) sorbents were used to sorb oil from water, and their sorption capacities and mechanisms were compared. Paired t test showed there was significant difference in the sorption capacities of modified and unmodified sorbents. Sorption of oil from water was found to be time and concentration dependent. Equilibrium studies showed that CP has higher sorption capacity than OPEFB and acetylation enhanced the crude sorption capacities of the sorbents. Crude oil sorption from water is a monolayer process that might have progressed from multilayer processes. Kinetic studies showed that sorption of crude oil by the sorbents was diffusion-controlled with the aid of physisorption and chemisorption mechanisms. Fourier transform infrared and scanning electron microscope analyses showed clear evidence of successful acetylation and oil sorption. Sorption ; Chemical engineering ; Chemistry ; Physisorption ; Fourier transform infrared spectroscopy ; Adsorption ; Cellulose ; Pulp and paper industry ; Organic chemistry ; Environmental chemistry ; Materials science Surface Modification and Superhydrophobicity
Authors: Manikant Singh | Michael A. Casbon | Michael J. Uren | James W. Pomeroy | Stefano Dalcanale | Serge Karboyan | P.J. Tasker | Man Hoi Wong | Kohei Sasaki | Akito Kuramata | Shigenobu Yamakoshi | Masataka Higashiwaki | Martin Kuball
Source: IEEE Electron Device Letters (article, 2018-08-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Pulsed Large Signal RF Performance of Field-Plated Ga<sub>2</sub>O<sub>3</sub> MOSFETs Comparison between pulsed and CW large signal RF performance of field-plated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> MOSFETs has been reported. Reduced self-heating when pulse resulted in a power added efficiency of 12%, drain efficiency of 22.4%, output power density of 0.13 W/mm, and maximum gain up to 4.8 dB at 1 GHz for a 2- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> gate length device. Increased power dissipation for higher <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\textsf {DS}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\textsf {DS}}$ </tex-math></inline-formula> resulted in a degradation in performance, which, thermal simulation showed, could be entirely explained by self-heating. Buffer and surface trapping contributions have been evaluated using gate and drain lag measurements, showing minimal impact on device performance. These results suggest that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> is a good candidate for future RF applications. MOSFET ; Materials science ; Optoelectronics ; Gallium arsenide ; Electrical engineering ; Radio frequency ; Electronic engineering ; Transistor ; Voltage ; Engineering Ga2O3 and related materials ; ZnO doping and properties ; GaN-based semiconductor devices and materials
Authors: Xinqi Chen | Wei Dai | Tian Wu | Wei Luo | Jianping Yang | Wan Jiang | Lianjun Wang
Source: Coatings (article, 2018-07-10)
Field: Materials Science — Materials Chemistry

Thin Film Thermoelectric Materials: Classification, Characterization, and Potential for Wearable Applications Thermoelectric technology has the ability to convert heat directly into electricity and vice versa. With the rapid growth of portable and wearable electronics and miniature devices, the self-powered and maintenance of free thermoelectric energy harvester is highly desired as a potential power supply. Thin film thermoelectric materials are lightweight, mechanically flexible, and they can be synthesized from abundant resources and processed with a low-cost procedure, which offers the potential to develop the novel thermoelectric devices and hold unique promise for future electronics and miniature accessories. Here, a general classification for thin film thermoelectric materials varied by material compositions, and thermoelectric properties depended on different measurement technique. Several new flexible thermoelectric strategies are summarized with the hope that they can inspire further development of novel thermoelectric applications. Thermoelectric effect ; Electronics ; Thermoelectric generator ; Thermoelectric materials ; Characterization (materials science) ; Materials science ; Electricity ; Wearable computer ; Thermoelectric cooling ; Nanotechnology ; Energy harvesting ; Engineering physics ; Mechanical engineering ; Computer science ; Process engineering ; Electrical engineering ; Energy (signal processing) ; Engineering ; Embedded system Advanced Thermoelectric Materials and Devices ; Thermal properties of materials ; Thermal Radiation and Cooling Technologies
Authors: Mao Quan | Xiaoxiao Wang | Liang Wu | Ilya D. Gridnev | Guoqiang Yang | Wanbin Zhang
Source: Nature Communications (article, 2018-06-04)
Field: Chemistry — Organic Chemistry

Ni(II)-catalyzed asymmetric alkenylations of ketimines Chiral allylic amines are not only present in many bioactive compounds, but can also be readily transformed to other chiral amines. Therefore, the asymmetric synthesis of chiral allylic amines is highly desired. Herein, we report two types of Ni(II)-catalyzed asymmetric alkenylation of cyclic ketimines for the preparation of chiral allylic amines. When ketimines bear alkyl or alkoxycarbonyl groups, the alkenylation gives five- and six-membered cyclic α-tertiary allylic amine products with excellent yields and enantioselectivities under mild reaction conditions. A variety of ketimines can be used and the method tolerates some variation in alkenylboronic acid scope. Furthermore, with alkenyl five-membered ketimine substrates, an alkenylation/rearrangement reaction occurs, providing seven-membered chiral sulfamide products bearing a conjugated diene skeleton with excellent yields and enantioselectivities. Mechanistic studies reveal that the ring expansion step is a stereospecific site-selective process, which can be catalyzed by acid (Lewis acid or Brønsted acid). Allylic rearrangement ; Chemistry ; Catalysis ; Amine gas treating ; Stereospecificity ; Alkyl ; Organic chemistry ; Conjugated system ; Enantioselective synthesis ; Ring (chemistry) ; Combinatorial chemistry ; Medicinal chemistry ; Polymer Synthesis and Catalytic Reactions ; Asymmetric Hydrogenation and Catalysis ; Synthetic Organic Chemistry Methods
Authors: Joonkyo Jung | Hyeonjin Park | Jun-Hyung Park | Taeyong Chang | Jonghwa Shin
Source: Nanophotonics (review, 2018-06-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Broadband metamaterials and metasurfaces: a review from the perspectives of materials and devices Abstract Metamaterials can possess extraordinary properties not readily available in nature. While most of the early metamaterials had narrow frequency bandwidth of operation, many recent works have focused on how to implement exotic properties and functions over broad bandwidth for practical applications. Here, we provide two definitions of broadband operation in terms of effective material properties and device functionality, suitable for describing materials and devices, respectively, and overview existing broadband metamaterial designs in such two categories. Broadband metamaterials with nearly constant effective material properties are discussed in the materials part, and broadband absorbers, lens, and hologram devices based on metamaterials and metasurfaces are discussed in the devices part. Metamaterial ; Broadband ; Bandwidth (computing) ; Materials science ; Photonic metamaterial ; Holography ; Computer science ; Optoelectronics ; Physics ; Optics ; Telecommunications Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis