jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Dacen Waters | Ruiheng Su | Ellis Thompson | Anna Okounkova | Esmeralda Arreguin-Martinez | Minhao He | Katherine Hinds | Kenji Watanabe | Takashi Taniguchi | Xiaodong Xu | Yahui Zhang | Joshua Folk | Matthew Yankowitz
Source: Nature Communications (article, 2024-12-04)
Field: Materials Science — Materials Chemistry

Topological flat bands in a family of multilayer graphene moiré lattices Moiré materials host a wealth of intertwined correlated and topological states of matter, all arising from flat electronic bands with nontrivial quantum geometry. A prominent example is the family of alternating-twist magic-angle graphene stacks, which exhibit symmetry-broken states at rational fillings of the moiré band and superconductivity close to half filling. Here, we introduce a second family of twisted graphene multilayers made up of twisted sheets of M- and N-layer Bernal-stacked graphene flakes. Calculations indicate that applying an electric displacement field isolates a flat and topological moiré conduction band that is primarily localized to a single graphene sheet below the moiré interface. Phenomenologically, the result is a striking similarity in the hierarchies of symmetry-broken phases across this family of twisted graphene multilayers. Our results show that this family of structures offers promising new opportunities for the discovery of exotic new correlated and topological phenomena, enabled by using the layer number to fine tune the flat moiré band and its screening environment. Graphene ; Topological insulator ; Moiré pattern ; Condensed matter physics ; Topology (electrical circuits) ; Materials science ; Physics ; Nanotechnology ; Optics Graphene research and applications ; Topological Materials and Phenomena ; Quantum and electron transport phenomena
Authors: Luca M. Cavinato | Veronika Kost | Sergi Campos‐Jara | Sara Ferrara | Sanchari Chowdhury | Irene M. N. Groot | Tatiana Da Ros | Rubén D. Costa
Source: Advanced Optical Materials (article, 2024-06-21)
Field: Materials Science — Materials Chemistry

Blue‐Emitting Boron‐ and Nitrogen‐Doped Carbon Dots for White Light‐Emitting Electrochemical Cells Abstract This work describes the first use of blue‐emitting boron‐ and nitrogen‐doped carbon dots (BN‐CDs), rationalizing their photoluminescence behavior in solution and ion‐based thin‐films to prepare white light‐emitting electrochemical cells (LECs). In detail, a cost‐effective and scalable water‐based microwave‐assisted synthesis procedure is set for BN‐CDs featuring an amorphous carbon‐core doped with N and B. While they show a bright (photoluminescence quantum yield of 42%) and excitation‐independent blue‐emission (440 nm) in solution related to emitting n−π * surface states, they are not emissive in thin‐films due to aggregation‐induced quenching. Upon fine‐tuning the film composition (ion‐based host), an excitation dependent emission covering the whole visible range is noted caused by interaction of the ion electrolyte with the peripheral functionalization of the BN‐CDs. Moreover, the efficient energy transfer from the host to the BN‐CDs emitting species enabled good performing LECs with white emission ( x/y CIE coordinates of 0.30/0.35, correlated color temperature of 6795 K, color rendering index of 87) and maximum luminance of 40 cd m −2 , and stabilities of a few hours. This represents a significant improvement compared to the prior‐art monochromatic CD‐based LECs with similar brightness levels, but stabilities of &lt;1 min. Materials science ; Boron ; White light ; Doping ; Optoelectronics ; Electrochemistry ; Carbon fibers ; Nanotechnology ; Composite material ; Electrode ; Organic chemistry Carbon and Quantum Dots Applications ; Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research
Authors: Liqiu Yang | Ying Wang | Wenyu Yuan | Quan‐Guo Zhai
Source: Small (article, 2024-12-23)
Field: Chemistry — Inorganic Chemistry

Shifting C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> Adsorption and Separation in Pillar‐Layered Metal–Organic Frameworks Finely‐Regulated by Molecular Rotation The efficient separation of C₂H₂/CO₂ mixture is crucial for industrial applications. A promising strategy is proposed herein to fine-tune the C₂H₂/CO<sub>2</sub> adsorption and separation by pillar-layered metal-organic framework (MOF) adsorbents via molecular rotation. Keeping the same ultramicroporous architecture, three Zn-X-TRZ (TRZ = 1,2,4-triazole) adsorbents are prepared with X-pillar rotors varying from 9,10-anthracenedicarboxylic acid (ADC), 1,4-naphthalenedicarboxylic acid (NDC) to 1,4-benzenedicarboxylic acid (BDC). Remarkably, the introduction of the largest ADC rotors enables Zn-ADC-TRZ with superior C₂H₂-selective thermodynamic-separation ability (highest heat of adsorption and IAST selectivity values) but poor dynamic-separation performance caused by steric hindrance. Conversely, Zn-BDC-TRZ with the smallest rotors exhibit moderate CO₂-selective thermodynamic-separation ability, but excellent CO<sub>2</sub>/C₂H₂ dynamic-separation ability with high-purity C₂H₂ produced at 298 K (>99.5% obtained from 70% C₂H₂ mixture and >99.95% from 90% C₂H₂ mixture). In contrast, Zn-NDC-TRZ with medium NDC rotors shows comparable interactions and steric hindrance with C₂H₂ and CO₂, making both the thermodynamic and dynamic C₂H₂/CO₂ separation are unfavorable. Overall, controllable adsorption of C₂H₂ and CO<sub>2</sub> is successfully achieved and shifted from C<sub>2</sub>H<sub>2</sub>-selective to CO₂-selective separation regulated by the pillared molecular rotation within pillar-layered MOFs, providing a useful route for practical gas adsorbent exploration. Steric effects ; Adsorption ; Metal-organic framework ; Selectivity ; Pillar ; Gas separation ; Materials science ; Metal ; Selective adsorption ; Molecule ; Chemical engineering ; Chemistry ; Physical chemistry ; Stereochemistry ; Organic chemistry ; Catalysis ; Membrane Metal-Organic Frameworks: Synthesis and Applications ; Covalent Organic Framework Applications ; Carbon Dioxide Capture Technologies
Authors: Chinju Govind | Evangelos Balanikas | Gana Sanil | Daniel T. Gryko | Eric Vauthey
Source: Chemical Science (article, 2024-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Structural and solvent modulation of symmetry-breaking charge-transfer pathways in molecular triads Whereas the photoinduced charge-transfer properties of electron donor-acceptor dyads are now well understood, those of symmetric conjugated architectures containing several identical donor-acceptor branches have started to be scrutinised much more recently. Here, we report on our investigation of the charge-transfer dynamics of a series of formally centrosymmetric triads consisting of a quadrupolar dihydropyrrolopyrrole core substituted with two identical diphenylethynyl lateral branches. Using a combination of time-resolved electronic and vibrational spectroscopies, we show that these molecules exhibit rich excited-state dynamics, which includes three different types of symmetry-breaking charge-transfer processes depending on the nature of the end substituents on the core and branches as well as on the solvent: (i) excited-state symmetry breaking within the core; (ii) charge transfer from the core to one of the two branches; (iii) charge transfer between the two branches. This investigation illustrates how the excited-state properties of symmetric conjugated molecules, including the nature and location of the exciton, can be controlled by fine tuning structural as well as environmental parameters. Charge (physics) ; Modulation (music) ; Chemical physics ; Solvent ; Symmetry (geometry) ; Chemistry ; Transfer (computing) ; Symmetry breaking ; Physics ; Quantum mechanics ; Computer science ; Organic chemistry ; Mathematics Photochemistry and Electron Transfer Studies ; Porphyrin and Phthalocyanine Chemistry ; Synthesis and Properties of Aromatic Compounds
Authors: Yaoyao Peng | Lewang Yuan | Kang-Kai Liu | Zong‐Jie Guan | Shangbin Jin | Yu Fang
Source: Angewandte Chemie (article, 2024-12-23)
Field: Materials Science — Materials Chemistry

Photosynthesis of H<sub>2</sub>O<sub>2</sub> using Phenothiazine‐Based Covalent‐Organic Frameworks Mimicking Coenzyme Q Abstract Mimicking natural enzymes through artificial enzyme engineering represents a powerful strategy to fine‐tune the performance of photocatalysts, while the manipulation of electron transfer systems through atomic precision control is challenging. Herein, we reported a series of covalent organic frameworks (COFs) based on progressively oxidized phenothiazine (PTH) core as the platform for emulating Coenzyme Q, achieved through meticulous stepwise adjustments of their redox states. Compared to the original PTH‐S‐COF , the COFs with incrementally oxidized sulfur sites exhibited enhanced charge transfer efficiencies, facilitating efficient electron donation to O 2 and thereby providing a favorable pathway for H 2 O 2 synthesis. Notably, the PTH‐SO 2 ‐COF achieved a remarkable synthesis rate of 7755 μmol g −1 h −1 , marking a 720 % improvement over the PTH‐S‐COF baseline. Furthermore, upon adjusting the sacrificial agent ratio, this rate soared to an impressive 13565 μmol g −1 h −1 , surpassing the most reported photo‐active COFs. In situ characterizations and simulations verified that three H 2 O 2 evolution pathways (2e − ORR, 4e − OER, and 4e − ORR) all involved in the H 2 O 2 production process. As a result, our findings introduce a novel pathway for the development of high‐performance COF‐based photocatalysts through the innovative application of artificial enzyme‐mimicking techniques. Electron transfer ; Covalent bond ; Phenothiazine ; Covalent organic framework ; Cofactor ; Combinatorial chemistry ; Chemistry ; Redox ; Sulfur ; Artificial photosynthesis ; Nanotechnology ; Materials science ; Enzyme ; Photochemistry ; Organic chemistry ; Catalysis ; Biology Covalent Organic Framework Applications ; Advanced Photocatalysis Techniques ; Caching and Content Delivery
Authors: N. V. Srihari | Sumanth Bayari | M.V. Santhosh Kumar | Mahesh Padaki | K.K. Nagaraja
Source: Physica Scripta (article, 2024-05-23)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Comprehensive investigation into the influence of oxygen vacancies on the ferroelectric properties of spin coated bismuth ferrite thin films Abstract Bismuth ferrite (BFO) is a prime candidate for room-temperature magnetoelectric coupling and multiferroic applications. The rhombohedral R3c phase of BFO is the source of many properties, but the phase purity and oxygen vacancies are still the biggest obstacles to its real-world application. Considering these facts, the present work investigates the effects of oxygen vacancies on the functional properties through manipulation of drying temperatures of spin-cast films, especially at temperatures around 280 °C, where both the secondary phase and oxygen vacancies are prevalent. One of the biggest sources of oxygen vacancy is bismuth volatilisation, and our work deals with the situation head-on, uncovering the effect of bismuth volatilisation on functional properties. The structural properties were studied using x-ray diffraction (XRD), and deeper insights into the surface topography of the samples were obtained using AFM imaging. The electrical and dielectric characteristics help distinguish and analyse the samples in terms of the presence of resistive switching. PUND studies were performed to determine the ferroelectric properties of the samples. A fifty percent reduction in the oxygen vacancies in the presence of secondary phases was observed when compared with the phase-pure sample, as shown by the XPS analysis. Deeper insights were provided into the valence band spectra by first-principles studies. This work shows that phase purity may not be the singular condition for enhancing functional properties, and fine-tuning the presence of secondary phases and oxygen vacancies may be the way forward. The ferroelectric polarisation in one of the samples exhibits a notably higher value when using chemical solution deposition methods, making it a promising candidate for memory devices. Bismuth ferrite ; Materials science ; Bismuth ; Ferroelectricity ; Condensed matter physics ; Oxygen ; Ferrite (magnet) ; Thin film ; Spin (aerodynamics) ; Nanotechnology ; Multiferroics ; Metallurgy ; Optoelectronics ; Composite material ; Thermodynamics ; Chemistry ; Physics ; Dielectric Multiferroics and related materials ; Ferroelectric and Piezoelectric Materials ; Heusler alloys: electronic and magnetic properties
Authors: Junhao Xu | Bing Wang | Guangli Shi | Tengbo Hu | Piaoping Yang | Ye Kuang | Longhai Shen
Source: Ceramics International (article, 2024-03-03)
Field: Materials Science — Materials Chemistry

Exploring energy mechanisms involved in the luminescence reduction due to Ce3+ doping via core-multishell upconversion nanoparticles highly doped with Ho3+ and Yb3+ Materials science ; Doping ; Photon upconversion ; Ion ; Luminescence ; Dopant ; Nanotechnology ; Nanoparticle ; Transmission electron microscopy ; Analytical Chemistry (journal) ; Chemical engineering ; Optoelectronics ; Chemistry Luminescence Properties of Advanced Materials ; Radiation Detection and Scintillator Technologies ; Luminescence and Fluorescent Materials
Authors: Shuang Zhou | Tianyu Qiu | Wang He | Boyan Tang | Yang Su | Tianhao Nan | Junchao Dong | Zihao Wang | Dongtao Liu | Guangshan Zhu
Source: Chemical Science (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Flexible porous organic polymers constructed using C(sp<sup>3</sup>)–C(sp<sup>3</sup>) coupling reactions and their high methane-storage capacity Carbon-carbon coupling is a basic design principle for the synthesis of porous organic polymers, which are widely used in gas adsorption/separation, photocatalysis, energy storage, <i>etc.</i> However, the C(sp<sup>3</sup>)-C(sp<sup>3</sup>) coupling reaction to construct porous organic polymers remains an important yet elusive objective due to its low reactivity and unknown side reactions. Herein, we report that nickel bis(1,5-cyclooctadiene) (Ni(COD)<sub>2</sub>), which was a famous catalyst for C(sp<sup>2</sup>)-C(sp<sup>2</sup>) coupling reactions, enables highly efficient C(sp<sup>3</sup>)-C(sp<sup>3</sup>) homo-coupling reactions to construct porous linear crystalline polymers and flexible three-dimensional porous aromatic frameworks (PAFs) under mild reaction conditions. The resulting linear polymers generated with dibromomethyl arenes have good crystallinity and high melting points (<i>T</i> <sub>m</sub> = 286 °C) due to controllability of reaction sites. Furthermore, the PAFs (PAF-64, PAF-65 and PAF-66) stemmed from tri-/tetra-bromomethyl arenes show high surface area (<i>S</i> <sub>BET</sub> = 390 m<sup>2</sup> g<sup>-1</sup>) and high methane-storage capacity (up to 313 cm<sup>3</sup> cm<sup>-3</sup>) because of their flexible frameworks. This work sheds new light on the construction of novel porous polymers through C(sp<sup>3</sup>)-C(sp<sup>3</sup>) coupling reactions and the development of methane-storage materials. Polymer ; Methane ; Porosity ; Swelling ; Coupling (piping) ; Porous medium ; Organic polymer ; Chemical engineering ; Materials science ; Coupling reaction ; Polymer chemistry ; Chemistry ; Organic chemistry ; Composite material ; Catalysis Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Luminescence and Fluorescent Materials
Authors: Ludovic Zaza | Dragos Stoian | Noah Bussell | Petru P. Albertini | Coline Boulanger | Jari Leemans | Krishna Kumar | Anna Loiudice | Raffaella Buonsanti
Source: Journal of the American Chemical Society (article, 2024-11-14)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Increasing Precursor Reactivity Enables Continuous Tunability of Copper Nanocrystals from Single-Crystalline to Twinned and Stacking Fault-Lined Colloidal nanocrystals (NCs) are active materials in different applications, wherein their shape dictates their properties, such as optical or catalytic properties, and, thus, their performance. Hence, learning to tune the NC shape is an important goal in chemistry, with implications in other fields of research. A knowledge gap exists in the chemistry of non-noble metals, wherein design rules for shape control of NCs are still poorly defined compared to those of other classes of materials. Herein, we demonstrate that tuning the precursor reactivity is crucial to obtaining a continuous shape modulation from single-crystalline to twinned and stacking fault-lined Cu NCs. This tunability is unprecedented for non-noble metal NCs. We achieve this result by using diphenylphosphine in place of the most commonly used trioctylphosphine. Using in situ X-ray absorption spectroscopy, we show that the temperature modifies the reaction kinetics of an in situ-forming copper(I)bromide-diphenylphosphine complex during the synthesis of Cu NCs. We propose the presence of a P-H functionality in the phosphine to explain the higher reactivity of this precursor complex formed with diphenylphosphine compared to that formed with trioctylphosphine. This work inspires future studies on the role of phosphine ligands during the synthesis of Cu NCs to rationally target new morphologies, such as high-index faceted Cu NCs, and can be conceptually translated to other transition-metal NCs. Chemistry ; Stacking ; Copper ; Nanocrystal ; Reactivity (psychology) ; Crystallography ; Nanotechnology ; Organic chemistry Gold and Silver Nanoparticles Synthesis and Applications ; Machine Learning in Materials Science ; Nanomaterials for catalytic reactions
Authors: Spyridon Efstathiou | Gabit Nurumbetov | Andrew Ross | Yongguang Li | David M. Haddleton
Source: Materials Advances (article, 2024-01-01)
Field: Chemistry — Organic Chemistry

Moisture-cured solvent free silylated poly(ether-urea) pressure-sensitive adhesives (PSAs) for use as skin adhesives for application in transdermal drug delivery (TDD) Improving the adhesion and tack of pressure-sensitive adhesives (PSAs) in the absence of tackifier resins or fillers remains an ongoing challenge. Transdermal ; Adhesive ; Pressure sensitive ; Materials science ; Ether ; Adhesion ; Solvent ; Polymer chemistry ; Composite material ; Chemistry ; Organic chemistry ; Pharmacology Advanced Polymer Synthesis and Characterization ; Synthesis and properties of polymers ; Photopolymerization techniques and applications
Authors: Yohan Gisbert | Maximillian Fellert | Charlotte N. Stindt | Alexander Gerstner | Ben L. Feringa
Source: Journal of the American Chemical Society (article, 2024-04-24)
Field: Chemistry — Organic Chemistry

Molecular Motors’ Magic Methyl and Its Pivotal Influence on Rotation Molecular motors have found a wide range of applications, powering a transition from molecules to dynamic molecular systems for which their motion must be precisely tuned. To achieve this adjustment, strategies involving laborious changes in their design are often used. Herein, we show that control over a single methyl group allows a drastic change in rotational properties. In this regard, we present the straightforward asymmetric synthesis of β-methylated first-generation overcrowded-alkene-based molecular motors. Both enantiomers of the new motors were prepared in good yields and high enantiopurities, and these motors were thoroughly studied by variable-temperature nuclear magnetic resonance (VT-NMR), ultraviolet-visible (UV-vis), and circular dichroism (CD) spectroscopy, showing a crucial influence of the methylation pattern on the rotational behavior of the motors. Starting from a common chiral precursor, we demonstrate that subsequent methylation can drastically reduce the speed of the motor and reverse the direction of the rotation. We show for the first time that complete unidirectionality can be achieved even when the energy difference between the stable and metastable states is small, resulting in the coexistence of both states under ambient conditions without hampering the energy ratcheting process. This discovery opens the way for the design of more advanced first-generation motors. Molecular motor ; Chemistry ; Rotation around a fixed axis ; Metastability ; Rotation (mathematics) ; Nuclear magnetic resonance spectroscopy ; Spectroscopy ; Ultraviolet ; Molecule ; Rotational energy ; Nanotechnology ; Chemical physics ; Optoelectronics ; Stereochemistry ; Atomic physics ; Organic chemistry ; Physics ; Materials science Supramolecular Chemistry and Complexes ; Advanced NMR Techniques and Applications ; Photoreceptor and optogenetics research
Authors: Wenyu Wu | Lucie Perret | Patrick Rupper | Sandro Lehner | Xiaoyu Zhou | Henrik Eliasson | Rico Muff | Manfred Heuberger | Sabyasachi Gaan
Source: Green Chemistry (article, 2024-01-01)
Field: Materials Science — Biomaterials

A facile methodology for side- and upcycling of HDPE waste <i>via</i> partial creation of unsaturated double bonds We present a facile chemical method for converting HDPE waste into valuable long-chain dicarboxylic acids (LCDCAs), thus transforming polymer waste into monomers for potentially novel polyester synthesis. High-density polyethylene ; Monomer ; Polyester ; Side chain ; Double bond ; Polymer ; Materials science ; Chemistry ; Organic chemistry ; Polymer chemistry ; Chemical engineering ; Polyethylene biodegradable polymer synthesis and properties ; Carbon dioxide utilization in catalysis ; Chemistry and Chemical Engineering
Authors: Julien Devos | Vitaly L. Sushkevich | Ibrahim Khalil | Sven Robijns | Rodrigo de Oliveira Silva | Dimitrios Sakellariou | Jeroen van Bokhoven | Michiel Dusselier
Source: Journal of the American Chemical Society (article, 2024-09-19)
Field: Chemistry — Inorganic Chemistry

Enhancing the Acidity Window of Zeolites by Low-Temperature Template Oxidation with Ozone Revisiting the impact of the first and often deemed trivial postsynthetic step, i.e., a high-temperature oxidative calcination to remove organic templates, increases our understanding of thermal acid site evolution and Al distributions. An unprecedented degree of control over the acidity of high-silica zeolites (SSZ-13) was achieved by using a low-temperature ozonation approach. Fourier transform infrared spectroscopy of adsorbed probe molecules and solid-state NMR spectroscopy reveal the complexity of the thermal evolution of acid sites. Low-temperature activated (ozonated) zeolites maintain the original Brønsted acidity content and high defect content and have virtually no Lewis acidity. They also preserve the "as-made" Al distribution after crystallization and show a clear link between synthesis conditions and divalent cation capacity, as measured with aqueous cobalt ion uptake. The synthesis protocol is found to be the main contributor to Al proximity, yielding record high exchange capacity when ozonated. After conventional calcination at 500-600 °C, however, the presence of water leads to the gradual depletion of Brønsted acid sites, in particular, in small crystals. This work indicates that low-temperature ozonation followed by thermal activation at different temperatures can be used as a novel tool for tuning the amount and nature of acid sites, providing insights into the activity of zeolites in acid-catalyzed reactions, such as CO<sub>2</sub> hydrogenation to dimethyl ether, and thereby expanding the possibilities of rational acidity tuning. Chemistry ; Ozone ; Catalysis ; Zeolite ; Window (computing) ; Inorganic chemistry ; Chemical engineering ; Organic chemistry Zeolite Catalysis and Synthesis ; Catalysis and Oxidation Reactions ; Catalytic Processes in Materials Science