jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Fernando J. Urbanos | Andrés Black | Ramón Bernardo Gavito | Amadeo L. Vázquez de Parga | Rodolfo Miranda | Daniel Granados
Source: Nanoscale (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Electrical and geometrical tuning of MoS<sub>2</sub> field effect transistors <i>via</i> direct nanopatterning Mechanically exfoliated van der Waals materials can be used to prepare proof-of-concept electronic devices. Their optoelectronic properties strongly depend on the geometry and number of layers present in the exfoliated flake. Once the device fabrication steps have been completed, tuning the device response is complex, since the geometry and number of layers cannot be easily modified. In this work, we employ Pulsed Focused Electron Beam Induced Etching (PFEBIE) to tailor the geometry and electronic properties of field effect transistors based on mechanically exfoliated Molybdenum Disulfide (MoS<sub>2</sub>) flakes. First, MoS<sub>2</sub> field effect transistors are fabricated via optical lithography and conventional methods. Then, the geometry of the MoS<sub>2</sub> source-drain conduction channel is modified employing a Xenon difluoride (XeF<sub>2</sub>) gas injection nozzle combined with a pulsed electron beam pattern-generation system. Electrical characterization of devices carried out before and after the nanopatterning step via PFEBIE reveals a shift in the doping from N-type towards P-type. We attribute this change to sulfur vacancies induced during the direct nanopatterning step. This is confirmed by micro-Raman and micro-Photoluminescence spectroscopy experiments. The direct nanopatterning method allows us to fine-tune the geometry and thus the electronic properties of the devices, once the conventional fabrication steps have been completed. The success rate of our tailoring method exceeds 85% when tuning the geometry of the flake into a 250 nm wide and straight conduction channel between source and drain. Materials science ; Field-effect transistor ; Transistor ; Optoelectronics ; Nanotechnology ; Field (mathematics) ; Electrical engineering ; Voltage ; Engineering 2D Materials and Applications ; MXene and MAX Phase Materials ; Nanowire Synthesis and Applications
Authors: Manjari Shukla | Soma Banik | R. K. Pandey | Chandan Upadhyay
Source: Journal of Physics Condensed Matter (article, 2019-11-21)
Field: Materials Science — Materials Chemistry

Role of chemical pressure on optical and electronic structure of Ho <sub>2</sub> Ge <sub> <i>x</i> </sub> Ti <sub> 2− <i>x</i> </sub> O <sub>7</sub> Chemical pressure plays a crucial role in determining the electronic properties of the quantum materials. Investigation of electronic structure of Ho<sub>2</sub>Ge <sub>x</sub> Ti<sub>2-x</sub> O<sub>7</sub> (x = 2, 1.9, 1.75, 1.5 1, 0.5, 0.25, 0.1 and 0) series has been performed. Pyrochlore and Pyrogermanate, Re<sub>2</sub>B<sub>2</sub>O<sub>7</sub> (Re = Ho<sup>3+</sup>, B = Ti<sup>4+</sup> and Ge<sup>4+</sup>; rare earth titanates and germanates), substituted with increasing amount of Ge<sup>4+</sup> at the Ti<sup>4+</sup> site and vice versa develops structural distortions. Distinct shrinkage effect has been established in the Ho<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> matrix upon Ge<sup>+4</sup> substitutions at B site, resulting in the modification of band gap value. Band gap of 5.24 eV drastically drops to 3.92 eV with immediate Ti<sup>4+</sup> substitution in Ho<sub>2</sub>Ge<sub>2</sub>O<sub>7</sub>. Electronic states of Ho<sup>3+</sup> (4f forbidden transitions) had also been identified. We observe favored sub level transition (Specific Stark component) corresponding to<sup>5</sup>F<sub>5</sub> to <sup>5</sup>I<sub>8</sub> electronic transition for Ho<sup>3+</sup> at λ <sub>exc.</sub> = 450 nm. The upper valence band consisted of O 2p state hybridized with Ho 5p and Ti and Ge 4p states and conduction band primarily formed by Ho 5d state hybridized with Ti 3d and Ge 4d states as obtained from density of states (DOS) calculations. Strong hybridization between Ho 5p<sub>1/2</sub> and Ti 3p orbital upon Ti<sup>4+</sup> inclusion in Ho<sub>2</sub>Ge<sub>2</sub>O<sub>7</sub> has been observed through both theoretical studies using LDA-1/2 and UV-Vis, photoluminescence, ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy. The evolution of total DOS of all studied composition shows that valence band edge is more sensitive than conduction band to composition. These results provide chemical pressure as an excellent tool to tailor the band gap and fine tune the intermediate electronic states in Ho<sub>2</sub>Ge <sub>x</sub> Ti<sub>2-x</sub> O<sub>7</sub>. Valence (chemistry) ; X-ray photoelectron spectroscopy ; Electronic structure ; Photoluminescence ; Band gap ; Pyrochlore ; Materials science ; Density of states ; Chemical bond ; Direct and indirect band gaps ; Ultraviolet photoelectron spectroscopy ; Spectroscopy ; Crystallography ; Condensed matter physics ; Chemistry ; Physics ; Nuclear magnetic resonance Nuclear materials and radiation effects ; Advanced Condensed Matter Physics ; Microwave Dielectric Ceramics Synthesis
Authors: Hossein Roohi | Parvaneh Alizadeh
Source: Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (article, 2019-02-18)
Field: Chemistry — Physical and Theoretical Chemistry

Fine-tuned dual fluorescence behavior of N-substituted aniline-imidazopyridine based switches: Mechanistic understanding, substituent and solvent effects Tautomer ; Chemistry ; Solvent ; Photochemistry ; Substituent ; Intramolecular force ; Molecule ; Excited state ; Proton ; Exergonic reaction ; Aniline ; Toluene ; Fluorescence ; Computational chemistry ; Stereochemistry ; Organic chemistry ; Catalysis Photochemistry and Electron Transfer Studies ; Luminescence and Fluorescent Materials ; Radical Photochemical Reactions
Authors: Niket S. Powar | R.S. Pandav
Source: Journal of Chemical Reviews (article, 2019-10-10)
Field: Materials Science — Materials Chemistry

Overview of Borophene as a Potential Candidate in 2D Materials Science for the Energy Applications Energy problem is one of the serious concerns in modern society; therefore, we have to take hastily an effective action. Hence, researchers are looking for some attractive materials with low-cost, lightweight, and environmentally effective. Recently, 2D materials have taken notable recognition in the field of materials science for multiple energy application, because of its unique electronic and optical properties; and borophene is one of the 2D material which is commendatories than graphene. However, it has not much experimentally explored yet. This review discusses the synthesis process of borophene and discussed energy-related application such as energy storage, optoelectronic, photocatalytic activity, and hydrogen storage. Moreover, this work provides a summary of each application that could help to understand the importance of borophene materials for energy applications. Borophene ; Nanotechnology ; Graphene ; Materials science ; Energy storage ; Work (physics) ; Process (computing) ; Computer science ; Process engineering ; Engineering physics ; Engineering ; Mechanical engineering ; Physics ; Power (physics) Boron and Carbon Nanomaterials Research ; Graphene research and applications ; Advancements in Battery Materials
Authors: Andreas Beil | Friederike A. Steudel | Christoph Bräuchle | Hansjörg Grützmacher | Leonhard Möckl
Source: Scientific Reports (article, 2019-04-12)
Field: Chemistry — Organic Chemistry

Bisacylphosphane oxides as photo-latent cytotoxic agents and potential photo-latent anticancer drugs Bisacylphosphane oxides (BAPOs) are established as photoinitiators for industrial applications. Light irradiation leads to their photolysis, producing radicals. Radical species induce oxidative stress in cells and may cause cell death. Hence, BAPOs may be suitable as photolatent cytotoxic agents, but such applications have not been investigated yet. Herein, we describe for the first time a potential use of BAPOs as drugs for photolatent therapy. We show that treatment of the breast cancer cell lines MCF-7 and MDA-MB-231 and of breast epithelial cells MCF-10A with BAPOs and UV irradiation induces apoptosis. Cells just subjected to BAPOs or UV irradiation alone are not affected. The induction of apoptosis depend on the BAPO and the irradiation dose. We proved that radicals are the active species since cells are rescued by an antioxidant. Finally, an optimized BAPO-derivative was designed which enters the cells more efficiently and thus leads to stronger effects at lower doses. Cytotoxic T cell ; Radical ; Apoptosis ; Irradiation ; Oxidative stress ; Cancer research ; Chemistry ; Cytotoxicity ; Photodissociation ; Antioxidant ; Programmed cell death ; Pharmacology ; Biophysics ; Medicine ; Biochemistry ; Photochemistry ; Biology ; In vitro Free Radicals and Antioxidants ; Photodynamic Therapy Research Studies ; Photochromic and Fluorescence Chemistry
Authors: Ngoc B. Nguyen | Cheng‐Han Chen | Yulong Zhang | Peng Zhao | Benjamin M. Wu | Reza Ardehali
Source: Nanomedicine Nanotechnology Biology and Medicine (article, 2019-04-23)
Field: Materials Science — Biomaterials

Harnessing the versatility of PLGA nanoparticles for targeted Cre-mediated recombination PLGA ; Recombination ; Nanotechnology ; Computational biology ; Nanoparticle ; Biology ; Genetics ; Materials science ; Gene Nanoparticle-Based Drug Delivery ; Graphene and Nanomaterials Applications ; Advanced Drug Delivery Systems
Authors: Vepika Kandjou | Miguel Hernáez | Beatriz Acevedo | Sonia Melendi-Espina
Source: Progress in Organic Coatings (article, 2019-10-03)
Field: Materials Science — Materials Chemistry

Interfacial crosslinked controlled thickness graphene oxide thin-films through dip-assisted layer-by-layer assembly means Materials science ; Graphene ; Fabrication ; Thin film ; Oxide ; Layer (electronics) ; Contact angle ; X-ray photoelectron spectroscopy ; Layer by layer ; Nanotechnology ; Nanometre ; Scanning electron microscope ; Composite material ; Chemical engineering Graphene research and applications ; Molecular Junctions and Nanostructures ; Nanowire Synthesis and Applications
Authors: Ru‐Qiang Lu | Xiaoyun Yan | Lei Zhu | Linlin Yang | Hang Qu | Xinchang Wang | Ming Luo | Yu Wang | Rui Chen | Xiaoye Wang | Yu Lan | Jian Pei | Wengui Weng | Haiping Xia | Xiaoyu Cao
Source: Nature Communications (article, 2019-12-02)
Field: Materials Science — Materials Chemistry

Unveiling how intramolecular stacking modes of covalently linked dimers dictate photoswitching properties Covalently linked π-stacked dimers represent the most significant platform for elucidating the relationship between molecular alignments and their properties. Here, we present the one-pot synthesis of two intramolecularly π-stacked dimers and disclose how intramolecular stacking modes dictate photoswitching properties. The dimer, which features cofacially stacked chromophores and geometrically favours intramolecular photochemical [2 + 2] cycloadditions, displays a nearly irreversible photoswitching behaviour. By contrast, the dimer, bearing crosswise stacked chromophores, is geometrically unfavourable for the cycloaddition and exhibits a highly reversible photoswitching process, in which the homolysis and reformation of carbon-carbon single bonds are involved. Moreover, the chiral carbon centres of both dimers endow these photoswitches with chirality and the separated enantiomers exhibit tuneable chiroptical properties by photoswitching. This work reveals that intramolecular stacking modes significantly influence the photochemical properties of π-stacked dimers and offers a design strategy toward chiral photoswitchable materials. Intramolecular force ; Stacking ; Chromophore ; Dimer ; Covalent bond ; Chirality (physics) ; Chemistry ; Photochemistry ; Chemical physics ; Materials science ; Stereochemistry ; Chiral symmetry ; Physics ; Organic chemistry Photochromic and Fluorescence Chemistry ; Photoreceptor and optogenetics research ; Porphyrin and Phthalocyanine Chemistry
Authors: Yili Ding | Chamakura V.N.S. Vara Prasad | Bingyun Wang
Source: Journal of Chemistry (article, 2019-05-12)
Field: Chemistry — Organic Chemistry

Advances in Chemical Synthesis of Fondaparinux Fondaparinux (trade name Arixtra) is a safe and efficacious anticoagulant, and it is chemically related to low-molecular-weight heparins such as enoxaparin. Fondaparinux is a synthetic pentasaccharide, and its synthesis is difficult and expensive. The high cost of fondaparinux thwarts its extensive worldwide usage. Over the last two decades, several research groups and pharmaceutical companies have been interested in finding efficient and practical methods for its synthesis. The present review discusses those strategies and their pros and cons in a comparative account. Fondaparinux ; Chemistry ; Anticoagulant ; Biochemical engineering ; Risk analysis (engineering) ; Business ; Surgery ; Venous thromboembolism ; Engineering Carbohydrate Chemistry and Synthesis ; Proteoglycans and glycosaminoglycans research ; Glycosylation and Glycoproteins Research
Authors: Ahmed H. Lotfallah | M. Isabel Burguete | Ignacio Alfonso | Santiago V. Luis
Source: Journal of Colloid and Interface Science (article, 2019-12-28)
Field: Materials Science — Biomaterials

Synthesis of second-generation self-assembling Gemini Amphiphilic Pseudopeptides Amphiphile ; Self-assembly ; Chemistry ; Aqueous solution ; Protonation ; Linker ; Aqueous medium ; Vesicle ; Ionic strength ; Spectroscopy ; Drug delivery ; Nanotechnology ; Chemical engineering ; Materials science ; Organic chemistry ; Polymer ; Copolymer ; Membrane ; Ion Supramolecular Self-Assembly in Materials ; Polydiacetylene-based materials and applications ; Luminescence and Fluorescent Materials
Authors: Mohamad Songolzadeh | Mansooreh Soleimani | Maryam Takht Ravanchi
Source: Petroleum Science (article, 2019-07-03)
Field: Chemistry — Inorganic Chemistry

Multi-response optimization of MIL-101 synthesis for selectively adsorbing N-compounds from fuels In this work, MIL-101, a metal organic framework, has been synthesized and examined in the adsorptive denitrogenation process. Due to the importance of adsorption capacity and selectivity, the effects of synthesis parameters including metal type, reagent ratio, time and temperature on the MIL-101 performance were investigated by measuring quinoline (QUI) separation from iso-octane. The optimum conditions were determined using a Taguchi experimental design and the multi-response optimization (multivariate statistical) method. Based on the arithmetic mean of normalized QUI adsorption capacity and QUI/dibenzothiophene (DBT) selectivity, as the objective function, the optimum value of synthesis parameters were found to be manganese as metal type in the structure, 180 °C for synthesis temperature, 15 h for synthesis time and 1.00 for reagent molar ratio. Under these conditions, QUI adsorption capacity and QUI/DBT selectivity were 19.3 mg-N/g-Ads. and 24.6, respectively. Accordingly, the arithmetic mean between normalized values of these measured parameters was equal to 1.10, which is in good agreement with the predicted value. The MIL-101 produced under optimum conditions was characterized by determining its specific surface area, X-ray powder diffraction patterns and Fourier transform infrared spectroscopy. Finally, isotherm and kinetic studies indicate that the Langmuir isotherm and pseudo-first-order model can successfully describe the experimental data. Selectivity ; Reagent ; Adsorption ; Chemistry ; Langmuir adsorption model ; Dibenzothiophene ; Response surface methodology ; Fourier transform infrared spectroscopy ; Taguchi methods ; Analytical Chemistry (journal) ; Chemical engineering ; Physical chemistry ; Organic chemistry ; Materials science ; Chromatography ; Catalysis Metal-Organic Frameworks: Synthesis and Applications ; Covalent Organic Framework Applications ; Catalysis and Hydrodesulfurization Studies
Authors: Lianzhen Cao | Xia Liu | Zhen Guo | Lianqun Zhou
Source: Micromachines (review, 2019-11-27)
Field: Materials Science — Materials Chemistry

Surface/Interface Engineering for Constructing Advanced Nanostructured Light-Emitting Diodes with Improved Performance: A Brief Review With the rise of nanoscience and nanotechnologies, especially the continuous deepening of research on low-dimensional materials and structures, various kinds of light-emitting devices based on nanometer-structured materials are gradually becoming the natural candidates for the next generation of advanced optoelectronic devices with improved performance through engineering their interface/surface properties. As dimensions of light-emitting devices are scaled down to the nanoscale, the plentitude of their surface/interface properties is one of the key factors for their dominating device performance. In this paper, firstly, the generation, classification, and influence of surface/interface states on nanometer optical devices will be given theoretically. Secondly, the relationship between the surface/interface properties and light-emitting diode device performance will be investigated, and the related physical mechanisms will be revealed by introducing classic examples. Especially, how to improve the performance of light-emitting diodes by using factors such as the surface/interface purification, quantum dots (QDs)-emitting layer, surface ligands, optimization of device architecture, and so on will be summarized. Finally, we explore the main influencing actors of research breakthroughs related to the surface/interface properties on the current and future applications for nanostructured light-emitting devices. Interface (matter) ; Materials science ; Diode ; Optoelectronics ; Nanometre ; Light-emitting diode ; Nanotechnology ; Quantum dot ; Nanoscopic scale ; Layer (electronics) Quantum Dots Synthesis And Properties ; ZnO doping and properties ; Perovskite Materials and Applications
Authors: S. Yılmaz | Murat Tomakin | Ahmet Ünverdi | Abdulaziz ABOGHALON
Source: GAZI UNIVERSITY JOURNAL OF SCIENCE (article, 2019-11-28)
Field: Materials Science — Materials Chemistry

A Study on Hydrothermal Grown CdS Nanospheres: Effects of Cd/S Molar Ratio The study reports the influences of altering of Cd/S molar ratio on some physical properties of hydrothermal grown CdS nanospheres. Cd/S molar ratios were chosen as 1:0.5, 1:1, 1:2, 1:3 and 1:4 in the stock solution. X-ray diffraction (XRD) data showed the occurrence of nano-amorphous CdS structure. Scanning electron microscopy (SEM) conclusions illustrated that increasing Cd/S molar ratio up to 1:3 caused a growth in the sphere size whereas further rising of Cd/S molar ratio led to smaller sphere size. The presence of Cd and S atoms in CdS structure was approved by Energy dispersive x-ray spectroscopy (EDS) analysis. Optimum transparency was found by Cd/S molar ratio of 1:3. Band gap scores of CdS nanospheres were determined to be above 2.60 eV that was bigger than bulk CdS (2.42 eV) because of quantum confinement effect. Photoluminescence (PL) results showed that a gradual decrease in each peak was attained upon increasing Cd/S molar ratio, which could be due to the formation non-radiative recombination phenomenon. Electrical data demonstrated that CdS nanosphere having Cd/S molar ratio of 1:1 exhibited the best carrier density (1.48´1015cm-3) and resistivity (1.27´103 Ω.cm) values. Thus, it can be deduced that Cd/S molar ratio of 1:3 was obtained to be optimum one since it possesses both bigger sphere size and better transparency, facilitating the effective use of CdS nanospheres in the solar cells. Photoluminescence ; Hydrothermal circulation ; Molar ; Scanning electron microscope ; Band gap ; Molar ratio ; Materials science ; Analytical Chemistry (journal) ; Molar concentration ; Amorphous solid ; Nuclear chemistry ; Chemistry ; Crystallography ; Chemical engineering ; Organic chemistry ; Composite material ; Catalysis Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Nanowire Synthesis and Applications
Authors: K. F. Ulbrich | Carlos Eduardo Maduro de Campos
Source: AIP Advances (article, 2019-04-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Stability of iron selenide nanophases prepared by mechanosynthesis We have recently reported a method for obtaining about 30% of tetragonal β-FeSe in coexistence with hexagonal δ-FeSe and α-Fe phases by ball milling under an inert atmosphere, starting from FexSe powders with x = 1.00, 1.25 or 1.50, in which the use of Fe1.25Se or Fe1.50Se leads to more than 93% of β-FeSe after annealing at 400 °C for 1 h under vacuum [K. F. Ulbrich and C. E. M. Campos, RSC Adv. 8(15), 8190–8198 (2018)]. In this paper, we describe the phase stability of the samples and reveal a remarkable δ→β phase transition with storage time. The β-FeSe phase content increased exponentially during the first 30 days of storage, reaching about 70% in Fe1.5Se. X-ray powder diffraction and Rietveld analysis were used to evaluate changes in crystal structure and microstructure. Aging had only a mild effect on the magnetization curves of the samples, suggesting that the magnetism of mechanically alloyed iron selenide is governed mainly by the content of α-Fe. Tetragonal crystal system ; Materials science ; Selenide ; Annealing (glass) ; Mechanosynthesis ; Magnetization ; Superparamagnetism ; Ball mill ; Microstructure ; Chemical engineering ; Magnetism ; Crystallography ; Crystal structure ; Metallurgy ; Chemistry ; Condensed matter physics Iron-based superconductors research ; Inorganic Chemistry and Materials ; MXene and MAX Phase Materials
Authors: Laura N. Neumann | Christoph Weder | Stephen Schrettl
Source: CHIMIA International Journal for Chemistry (article, 2019-04-12)
Field: Materials Science — Polymers and Plastics

Healing of Polymeric Solids by Supramolecular Means Equipping a polymeric material with the ability to heal an inflicted damage is a crucial advantage for many applications. The incorporation of reversible and dynamic supramolecular interactions into polymeric systems has proven to be a promising route towards such materials. In this article, recent developments in the field of healable materials are highlighted with a particular focus on the design principles, driving forces, and mechanisms that allow healing to occur. Supramolecular chemistry ; Nanotechnology ; Materials science ; Computer science ; Chemistry ; Organic chemistry Polymer composites and self-healing ; Hydrogels: synthesis, properties, applications ; Advanced Polymer Synthesis and Characterization