Interaction of graphene oxide with tannic acid: computational modeling and toxicity mitigation in .

Graphene oxide (GO) undergoes multiple transformations when introduced to biological and environmental media. GO surface favors the adsorption of biomolecules through different types of interaction mechanisms, modulating the biological effects of the material. In this study, we investigated the interaction of GO with tannic acid (TA) and its consequences for GO toxicity.

Unraveling the Spin-to-Charge Current Conversion Mechanism and Charge Transfer Dynamics at the Interface of Graphene/WS Heterostructures at Room Temperature.

We report experimental investigations of spin-to-charge current conversion and charge transfer (CT) dynamics at the interface of the graphene/WS van der Waals heterostructure. Pure spin current was produced by the spin precession in the microwave-driven ferromagnetic resonance of a permalloy film (Py=NiFe) and injected into the graphene/WS heterostructure through a spin pumping process. The observed spin-to-charge current conversion in the heterostructure is attributed to the inverse Rashba-Edelstein effect (IREE) at the graphene/WS interface.

Connecting Higher-Order Topology with the Orbital Hall Effect in Monolayers of Transition Metal Dichalcogenides.

Monolayers of transition metal dichalcogenides (TMDs) in the 2H structural phase have been recently classified as higher-order topological insulators (HOTIs), protected by C_{3} rotation symmetry. In addition, theoretical calculations show an orbital Hall plateau in the insulating gap of TMDs, characterized by an orbital Chern number. We explore the correlation between these two phenomena in TMD monolayers in two structural phases: the noncentrosymmetric 2H and the centrosymmetric 1T.

Stability and Rupture of an Ultrathin Ionic Wire.

Using a combination of in situ high-resolution transmission electron microscopy and density functional theory, we report the formation and rupture of ZrO_{2} atomic ionic wires. Near rupture, under tensile stress, the system favors the spontaneous formation of oxygen vacancies, a critical step in the formation of the monatomic bridge. In this length scale, vacancies provide ductilelike behavior, an unexpected mechanical behavior for ionic systems.

High-throughput inverse design and Bayesian optimization of functionalities: spin splitting in two-dimensional compounds.

The development of spintronic devices demands the existence of materials with some kind of spin splitting (SS). In this Data Descriptor, we build a database of ab initio calculated SS in 2D materials. More than that, we propose a workflow for materials design integrating an inverse design approach and a Bayesian inference optimization.

Machine Learning of Microscopic Ingredients for Graphene Oxide/Cellulose Interaction.

Understanding the role of microscopic attributes in nanocomposites allows one to control and, therefore, accelerate experimental system designs. In this work, we extracted the relevant parameters controlling the graphene oxide binding strength to cellulose by combining first-principles calculations and machine learning algorithms. We were able to classify the systems among two classes with higher and lower binding energies, which are well defined based on the isolated graphene oxide features.

At the Verge of Topology: Vacancy-Driven Quantum Spin Hall in Trivial Insulators.

Vacancies in materials structure─lowering its atomic density─take the system closer to the atomic limit, to which all systems are topologically trivial. Here we show a mechanism of mediated interaction between vacancies inducing a topologically nontrivial phase. Within an approach we explore topological transition dependence with the vacancy density in transition metal dichalcogenides.

Room-Temperature Negative Differential Resistance in Surface-Supported Metal-Organic Framework Vertical Heterojunctions.

The advances of surface-supported metal-organic framework (SURMOF) thin-film synthesis have provided a novel strategy for effectively integrating metal-organic framework (MOF) structures into electronic devices. The considerable potential of SURMOFs for electronics results from their low cost, high versatility, and good mechanical flexibility. Here, the first observation of room-temperature negative differential resistance (NDR) in SURMOF vertical heterojunctions is reported.

Conformational analysis of tannic acid: Environment effects in electronic and reactivity properties.

Polyphenols are natural molecules of crucial importance in many applications, of which tannic acid (TA) is one of the most abundant and established. Most high-value applications require precise control of TA interactions with the system of interest. However, the molecular structure of TA is still not comprehended at the atomic level, of which all electronic and reactivity properties depend.

Recent Advances in Immunosafety and Nanoinformatics of Two-Dimensional Materials Applied to Nano-imaging.

Two-dimensional (2D) materials have emerged as an important class of nanomaterials for technological innovation due to their remarkable physicochemical properties, including sheet-like morphology and minimal thickness, high surface area, tuneable chemical composition, and surface functionalization. These materials are being proposed for new applications in energy, health, and the environment; these are all strategic society sectors toward sustainable development. Specifically, 2D materials for nano-imaging have shown exciting opportunities in and models, providing novel molecular imaging techniques such as computed tomography, magnetic resonance imaging, fluorescence and luminescence optical imaging and others.

Disassembly of TEMPO-Oxidized Cellulose Fibers: Intersheet and Interchain Interactions in the Isolation of Nanofibers and Unitary Chains.

Cellulose disassembly is an important issue in designing nanostructures using cellulose-based materials. In this work, we present a combination of experimental and theoretical study addressing the disassembly of cellulose nanofibrils. Through 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated oxidation processes, combined with atomic force microscopy results, we show the formation of nanofibers with diameters corresponding to that of a single-cellulose polymer chain.

Converging Multidimensional Sensor and Machine Learning Toward High-Throughput and Biorecognition Element-Free Multidetermination of Extracellular Vesicle Biomarkers.

Extracellular vesicles (EVs) are a frontier class of circulating biomarkers for the diagnosis and prognosis of different diseases. These lipid structures afford various biomarkers such as the concentrations of the EVs () themselves and carried proteins (). However, simple, high-throughput, and accurate determination of these targets remains a key challenge.

Pair Distribution Function from Electron Diffraction in Cryogenic Electron Microscopy: Revealing Glassy Water Structure.

In recent years, cryogenic electron microscopy (Cryo-EM) has revolutionized the structure determination of wet samples and especially that of biological macromolecules. The glassy-water medium in which the molecules are embedded is considered an almost environment for biological samples. The local structure of amorphous ice is known from neutron- and X-ray-diffraction studies, techniques appropriate for much larger volumes than those used in cryo-EM.

Ambipolar Resistive Switching in an Ultrathin Surface-Supported Metal-Organic Framework Vertical Heterojunction.

Memristors (MRs) are considered promising devices with the enormous potential to replace complementary metal-oxide-semiconductor (CMOS) technology, which approaches the scale limit. Efforts to fabricate MRs-based hybrid materials may result in suitable operating parameters coupled to high mechanical flexibility and low cost. Metal-organic frameworks (MOFs) arise as a favorable candidate to cover such demands.

Exploring Two-Dimensional Materials Thermodynamic Stability via Machine Learning.

The increasing interest and research on two-dimensional (2D) materials has not yet translated into a reality of diverse materials applications. To go beyond graphene and transition metal dichalcogenides for several applications, suitable candidates with desirable properties must be proposed. Here we use machine learning techniques to identify thermodynamically stable 2D materials, which is the first essential requirement for any application.

Toward Realistic Amorphous Topological Insulators.

The topological properties of materials are, until now, associated with the features of their crystalline structure, although translational symmetry is not an explicit requirement of the topological phases. Recent studies of hopping models on random lattices have demonstrated that amorphous model systems show a nontrivial topology. Using calculations, we show that two-dimensional amorphous materials can also display topological insulator properties.

Simulations and Materials Chemistry in the Age of Big Data.

In this perspective, we discuss computational advances in the last decades, both in algorithms as well as in technologies, that enabled the development, widespread use, and maturity of simulation methods for molecular and materials systems. Such advances led to the generation of large amounts of data, which required the creation of several computational databases. Within this scenario, with the democratization of data access, the field now encounters several opportunities for data-driven approaches toward chemical and materials problems.

Controlling Topological States in Topological/Normal Insulator Heterostructures.

We have performed a systematic investigation of the nature of the nontrivial interface states in topological/normal insulator (TI/NI) heterostructures. On the basis of first principles and a recently developed scheme to construct ab initio effective Hamiltonian matrices from density functional theory calculations, we studied systems of realistic sizes with high accuracy and control over the relevant parameters such as TI and NI band alignment, NI gap, and spin-orbit coupling strength. Our results for IV-VI compounds show the interface gap tunability by appropriately controlling the NI thickness, which can be explored for device design.

Electronic transport properties of MoS nanoribbons embedded in butadiene solvent.

Transition metal dichalcogenides (TMDCs) are promising materials for applications in nanoelectronics and correlated fields, where their metallic edge states play a fundamental role in the electronic transport. In this work, we investigate the transport properties of MoS zigzag nanoribbons under a butadiene (CH) atmosphere, as this compound has been used to obtain MoS flakes by exfoliation. We use density functional theory combined with non-equilibrium Green's function techniques, in a methodology contemplating disorder and different coverages.

Decreasing Nanocrystal Structural Disorder by Ligand Exchange: An Experimental and Theoretical Analysis.

Nanocrystals (NCs) present unique physicochemical properties arising from their size and the presence of ligands. Comprehending and controlling the ligand-crystal interactions as well as the ligand exchange process is one of the central themes in NC science nowadays. However, the relationship between NC structural disorder and the ligand exchange effect in the NC atomic structure is not yet sufficiently understood.

Spin-Polarization Control Driven by a Rashba-Type Effect Breaking the Mirror Symmetry in Two-Dimensional Dual Topological Insulators.

Three-dimensional topological insulators protected by both the time reversal (TR) and mirror symmetries were recently predicted and observed. Two-dimensional materials featuring this property and their potential for device applications have been less explored. We find that, in these systems, the spin polarization of edge states can be controlled with an external electric field breaking the mirror symmetry.

Nanodots of transition metal dichalcogenides embedded in MoS and MoSe: first-principles calculations.

The energetic stability and the electronic properties of nanodots (NDs) composed of transition metal dichalcogenides, XS and XSe (with X = Mo, W and Nb) embedded in single layer MoS and MoSe hosts, were investigated based on first-principles calculations. We find that through a suitable combination of the ND and host materials it is possible to control the electron-hole localization. For instance, in NDs of WS in the MoS host we find the highest occupied (hole) states localized in the ND region, while the lowest unoccupied (electron) states spread out in the MoS host.

Dynamic covalent bond from first principles: Diarylbibenzofuranone structural, electronic, and oxidation studies.

A structure that can self-heal under standard conditions is a challenge faced nowadays and is one of the most promising areas in smart materials science. This can be achieved by dynamic bonds, of which diarylbibenzofuranone (DABBF) dynamic covalent bond is an appealing solution. In this report, we studied the DABBF bond formation against arylbenzofuranone (ABF) and O reaction (autoxidation).