1,319 results match your criteria: "Max-Planck-Institute for Solid State Research[Affiliation]"

Boosting Amino Acid Synthesis with WO Sub-Nanoclusters.

Adv Mater

January 2025

College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241002, P. R. China.

The conversion of nitrate-rich wastewater and biomass-derived blocks into high-value products using renewably generated electricity is a promising approach to modulate the artificial carbon and nitrogen cycle. Here, a new synthetic strategy of WO sub-nanoclusters is reported and supported on carbon materials as novel efficient electrocatalysts for nitrate reduction and its coupling with α-keto acids. In acidic solutions, the NH-NHOH selectivity can also optimized by adjusting the potential, with the total FE exceeding 80% over a wide potential range.

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Metal halide perovskites have shown exceptional potential in converting solar energy to electric power in photovoltaics, yet their application is hampered by limited operational stability. This stimulated the development of hybrid layered (two-dimensional, 2D) halide perovskites based on hydrophobic organic spacers, templating perovskite slabs, as a more stable alternative. However, conventional organic spacer cations are electronically insulating, resulting in charge confinement within the inorganic slabs, thus limiting their functionality.

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Recently, we investigated a number of so-called σ- and τ-functionals based on the adiabatic-connection fluctuation-dissipation theorem (ACFDT); particularly, extensions of the random phase approximation (RPA) with inclusion of an exchange kernel in the form of an antisymmetrized Hartree kernel. One of these functionals, based upon the approximate exchange kernel (AXK) of Bates and Furche, leads to a nonlinear contribution of the spline function used within σ-functionals, which we previously avoided through the introduction of a simplified "top-down" approach in which the σ-functional modification is inserted a posteriori following the analytic coupling strength integration within the framework of the ACFDT and which was shown to provide excellent performance for the GMTKN55 database when using hybrid PBE0 reference orbitals. In this work, we examine the analytic "bottom-up" approach in which the spline function is inserted a priori, i.

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A generalized extraction procedure for magnetic interactions using effective Hamiltonians is presented that is applicable to systems with more than two sites featuring local spins ≥ 1. To this end, closed, nonrecursive expressions pertaining to chains of arbitrary equal spins are derived with the graphical method of angular momentum. The method is illustrated by extracting magnetic couplings from ab initio calculations on a [CaMnO] cubane.

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Insight into the Origin of Second Harmonic Generation and Rational Design in the Metal Halide Borates.

Inorg Chem

January 2025

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian, P. R. China.

Metal halide borates are promising candidates for high-performance nonlinear optical (NLO) applications, yet the origins of their second harmonic generation (SHG) properties remain unclear. Using atom response theory combined with density functional theory calculations, this study investigates why halogen substitution leads to distinctly different SHG responses in halide monoborates (PbBOX) versus halide pentaborates (PbBOX). We find that the SHG origins vary between these two families due to differences in the strength of the Pb-X interactions.

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All-solid-state Li-ion batteries (ASSBs) represent a promising leap forward in battery technology, rapidly advancing in development. Among the various solid electrolytes, argyrodite thiophosphates Li6PS5X (X = Cl, Br, I) stand out due to their high ionic conductivity, structural flexibility, and compatibility with a range of electrode materials, making them ideal candidates for efficient and scalable battery applications. However, despite significant performance advancements, the sustainability and recycling of ASSBs remain underexplored, posing a critical challenge for achieving efficient circular processes.

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Thickness Dependent Structural Transition in Ph-BTBT-10 Thin Films and Stabilization of the Ubiquitous Interface Bilayer.

ACS Appl Mater Interfaces

January 2025

Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Campus UAB, Carrer dels Til·lers, s/n, Bellaterra, 08193 Barcelona, Spain.

The influence of the film/substrate interface and the role of film thickness on the structural transition temperature for thin films of the asymmetric BTBT derivative 7-decyl-2-phenyl[1]benzothieno[3,2-][1]-benzothiophene (Ph-BTBT-10) have been addressed by using Kelvin probe force microscopy (KPFM) and synchrotron grazing incidence wide angle X-ray scattering (GIWAXS). Our data strongly suggest that the structural transformation from a single-layer phase to the thermodynamically stable bilayer structure develops from the bottom of the film to its surface. Contrary to observations in other organic semiconductor films, notably, the thinner the Ph-BTBT-10 film, the lower is the transition temperature.

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Organic Metasurfaces with Contrasting Conducting Polymers.

Nano Lett

January 2025

Second Physics Institute, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.

Conducting polymers have emerged as promising active materials for metasurfaces due to their electrically tunable states and large refractive index modulation. However, existing approaches are often limited to infrared operation or single-polymer systems, restricting their versatility. In this Letter, we present organic metasurfaces featuring dual conducting polymers, polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT), to achieve contrasting dynamic optical responses at visible frequencies.

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Magnetotransport of conventional semiconductor based double layer systems with barrier suppressed interlayer tunneling has been a rewarding subject due to the emergence of an interlayer coherent state that behaves as an excitonic superfluid. Large angle twisted bilayer graphene offers unprecedented strong interlayer Coulomb interaction, since both layer thickness and layer spacing are of atomic scale and a barrier is no more needed as the twist induced momentum mismatch suppresses tunneling. The extra valley degree of freedom also adds richness.

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Bending Moiré in Twisted Bilayer Graphene.

J Phys Chem Lett

January 2025

CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China.

Moiré potentials caused by lattice mismatches significantly alter electrons in two-dimensional materials, inspiring the discovery of numerous unique physical properties. While strain modulates the structure and symmetry of the moiré potential, serving as a tuning mechanism for interactions, the impact of out-of-plane deformation, e.g.

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Diamond is an exceptional material with great potential across various fields owing to its interesting properties. However, despite extensive efforts over the past decades, producing large quantities of desired ultrathin diamond membranes for widespread use remains challenging. Here we demonstrate that edge-exposed exfoliation using sticky tape is a simple, scalable and reliable method for producing ultrathin and transferable polycrystalline diamond membranes.

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Article Synopsis
  • Researchers have uncovered that deoxidized SrTiO becomes metallic and superconducting at very low oxygen vacancy levels, challenging long-standing assumptions.
  • Detailed studies show that during thermal reduction, oxygen is lost at extremely low concentrations, leading to the formation of filaments along dislocation networks in the material.
  • The findings suggest a rethink of superconductivity models in self-doped SrTiO, proposing that the material behaves as a nano-composite with both insulating and metallic characteristics, facilitating polaronic coupling.
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Collective excitations of bound electron-hole pairs, i.e., excitons, are ubiquitous in condensed matter systems, and it has been shown that they can strongly couple to other degrees of freedom, such as spin, orbital, and lattice.

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The use of OpenAlex to produce meaningful bibliometric global overlay maps of science on the individual, institutional, and national levels.

PLoS One

December 2024

Science Policy and Strategy Department, Administrative Headquarters of the Max Planck Society, Munich, Germany.

The Social Systems Citations Theory (SSCT) is the most recent theory of citations integrating previous theories. It focuses on communications in science that are formally manifested as publications and citations in scientific communication networks. These networks can be observed and empirically studied by using science maps.

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Discerning order from chaos: characterising the surface structure of liquid gallium.

Mater Horiz

December 2024

MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand.

Liquid metal (LM) technologies are rapidly advancing in modern materials science, with low melting point metals playing a pivotal role in emerging applications. Recent studies reveal that doped liquid gallium systems form spectacular and diverse surface structures during cooling, [Tang , , 2021, , 431-439] sparking renewed interest in the possible geometric structuring at the surface of pure liquid gallium. Distinct from the known increase in surface density, this lateral surface order has long been hinted at experimentally and theoretically but has remained enigmatic.

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Article Synopsis
  • Research on cobalt-functionalized covalent organic frameworks (COFs) as oxygen evolution electrocatalysts lacks focus on identifying true active species for the oxygen evolution reaction (OER).
  • The study reveals that cobalt oxide nanoparticles are created from Co(II) ions in the COF when in alkaline conditions, and these nanoparticles are the main active species for oxygen evolution.
  • The findings underscore the importance of understanding the relationship between COFs and metal centers during electrochemical processes to ensure effective catalyst performance and advancements in green hydrogen production technologies.
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We present a simple and cost-efficient route for the preparation of sulfonated dihalo-monomers for the synthesis of hydrocarbon ionomers. After conventional monomer sulfonation, excess sulfuric acid is quantitatively removed by neutralization with BaCO. This leads to the precipitation of excess HSO as insoluble BaSO, which is easily separated from the sulfonated monomers in their soluble Ba-forms by filtration.

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Coupling subcycle THz pulses to a scanning tunneling microscope (STM) enables ultrafast spectroscopy at the atomic scale. This technique critically depends on the shape of the THz near-field waveform in the tunnel junction. We characterize the THz electric field waveform in the STM junction by electro-optic sampling of tip-scattered THz light (-EOS) and pulse correlation using the THz-induced current.

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We report on a new polymorph of silver antimonate AgSbO discovered with the use of high-pressure high-temperature synthesis at 16 GPa and 1380 °C. The crystal structure is determined from X-ray powder diffraction, and we find this new high-pressure phase crystallizes in monoclinic space group 2/ with the following values: = 8.4570(3) Å, = 9.

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Highly Accurate and Robust Constraint-Based Orbital-Optimized Core Excitations.

J Phys Chem A

November 2024

Chair of Theoretical Chemistry, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich D-81377, Germany.

Article Synopsis
  • The paper discusses an advanced method called COOX, which is adapted to calculate core excitations using a constraint-based approach in density functional theory (DFT).
  • COOX combines elements like spin-unrestricted formalism and relativistic corrections to deliver highly accurate results for core excitations in second- and third-period atoms, with small errors.
  • The method also shows strong performance for heavier atoms and is competitive with established techniques like ΔSCF, making it a valuable tool for simulating X-ray absorption spectra with better convergence and lower computational costs.
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Tip-enhanced photoluminescence (TEPL) measurements are performed with subnanometer spatial resolution on individual molecules decoupled from a metallic substrate by a thin NaCl layer. TEPL spectra reveal progressive fluorescence quenching with decreasing tip-molecule distance when electrons tunneling from the tip of a scanning tunneling microscope are injected at resonance with the molecular states. Rate equations based on a many-body model reveal that the luminescence quenching is due to a progressive population inversion between the ground neutral (S_{0}) and the ground charge (D_{0}^{-}) states of the molecule occurring when the current is raised.

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Insertion storage in battery electrodes and supercapacitive storage are typically considered to be independent phenomena and thus are dealt with in separate scientific communities. Using tailored experiments on titanium oxide thin films of various thicknesses, we demonstrate the simultaneous occurrence of both processes. For the interpretation of the entire storage profile encompassing both contributions, the (free) energies of the charge carriers in the mixed conductor and the neighboring phase are the only materials parameters required.

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Parallel molecular data storage by printing epigenetic bits on DNA.

Nature

October 2024

Center for Molecular Design and Biomimetics, Biodesign Institute, Arizona State University, Tempe, AZ, USA.

DNA storage has shown potential to transcend current silicon-based data storage technologies in storage density, longevity and energy consumption. However, writing large-scale data directly into DNA sequences by de novo synthesis remains uneconomical in time and cost. We present an alternative, parallel strategy that enables the writing of arbitrary data on DNA using premade nucleic acids.

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The discovery of high-temperature superconductivity in La_{3}Ni_{2}O_{7} at pressures above 14 GPa has spurred extensive research efforts. Yet, fundamental aspects of the superconducting phase, including the possibility of a filamentary character, are currently subjects of controversial debates. Conversely, a crystal structure with NiO_{6} octahedral bilayers stacked along the c-axis direction was consistently posited in initial studies on La_{3}Ni_{2}O_{7}.

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Charge density waves are wave-like modulations of a material's electron density that display collective amplitude and phase dynamics. The interaction with atomic impurities induces strong spatial heterogeneity of the charge-ordered phase. Direct real-space observation of phase excitation dynamics of such defect-induced charge modulation is absent.

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