2,705 results match your criteria: "National Institute for Materials Science: NIMS[Affiliation]"

Loading cocatalysts on semiconductor-based photocatalysts to create active reaction sites is a preferable method to enhance photocatalytic activity and a widely adopted strategy to achieve effective photocatalytic applications. Although theoretical calculations suggest that the broad density of states of noble metal cocatalysts, such as Pt, act as a recombination center, this has never been experimentally demonstrated. Herein, we employed pico-nano and nano-micro second transient absorption spectroscopy to investigate the often overlooked photogenerated holes, instead of the widely studied electrons on Pt- and Ni-loaded SrTiO to evaluate the effects of cocatalysts as a recombination center.

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Moiré superlattices formed in van der Waals (vdW) bilayers of 2D materials provide an ideal platform for studying previously undescribed physics, including correlated electronic states and moiré excitons, owing to the wide-range tunability of their lattice constants. However, their crystal symmetry is fixed by the monolayer structure, and the lack of a straightforward technique for modulating the symmetry of moiré superlattices has impeded progress in this field. Herein, a simple, room-temperature, ambient method for controlling superlattice symmetry is reported.

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Hollandite-type α-MnO exhibits exceptional promise in current industrial applications and in advancing next-generation green energy technologies, such as multivalent (Mg, Ca, and Zn) ion battery cathodes and aerobic oxidation catalysts. Considering the slow diffusion of multivalent cations within α-MnO tunnels and the catalytic activity at edge surfaces, ultrasmall α-MnO particles with a lower aspect ratio are expected to unlock the full potential. In this study, ultrasmall α-MnO (<10 nm) with a low aspect ratio (c/a ≈ 2) is synthesized using a newly developed alcohol solution process.

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Sodium borohydride dihydrate (NaBH·2HO) forms through dihydrogen bonding between the hydridic hydrogen of the BH ion and the protonic hydrogen of the water molecule. High-pressure structural changes in NaBH·2HO, observed up to 11 GPa through X-ray diffraction and Raman scattering spectroscopy, were analyzed to assess the influence of dihydrogen bonds on its crystal structure. At approximately 4.

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Ammonia Decomposition Catalyzed by Co Nanoparticles Encapsulated in Rare Earth Oxide.

J Phys Chem Lett

January 2025

Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.

We fabricated Co-based catalysts by the low-temperature thermal decomposition of R-Co intermetallics (R = Y, La, or Ce) to reduce the temperature of ammonia cracking for hydrogen production. The catalysts synthesized are nanocomposites of Co/RO with a metal-rich composition. In the Co/LaO catalyst derived from LaCo, Co nanoparticles of 10-30 nm size are enclosed by the LaO matrix.

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We demonstrate high-throughput evaluation of the half-metallicity of CoMnSi Heusler alloys by spin-integrated hard X-ray photoelectron spectroscopy (HAXPES) of composition-spread films performed with high-brilliance synchrotron radiation at NanoTerasu, which identifies the optimum composition showing the best half-metallicity. Co Mn Si composition-spread thin films for  = 10-40% with a thickness of 30 nm are fabricated on MgO(100) substrates using combinatorial sputtering technique. The 2-ordering and (001)-oriented epitaxial growth of CoMnSi are confirmed by X-ray diffraction for  = 18-40%.

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Fine-Tuning of the Sequential Self-Assembly of Entangled Polyhedra by Exploiting the Side-Chain Effect.

Chem Asian J

December 2024

Tokyo College, U-Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Mitsui Link Lab Kashiwanoha 1, FS CREATION, 6-6-2 Kashiwanoha, Kashiwa-shi, Chiba, 277-0882, Japan.

The control of the sequential self-assembly processes of highly entangled (AgL) (n=2,4,6,8) and AgL coordination polyhedra using side-chain effects was studied via the introduction of linear or branched side chains into the tripodal ligands. In addition to changes in the intermediate polyhedral species affording the multi- pathway process, disruption of the kinetic control of the sequential self-assembly was observed, thus demonstrating the utility of steric control for the construction of 3D-entangled molecular materials on the 5 nm scale with high molecular complexity.

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Precise control of assembled structures of quantum dots (QDs) is crucial for realizing the desired photophysical properties, but this remains challenging. Especially, the one-dimensional (1D) control is rare due to the nearly isotropic nature of QDs. Herein, we propose a novel strategy for controlling the 1D-arrangement range of cubic perovskite QDs in solution based on the morphological modification of a supramolecular polymer (SP) template.

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Hydrogen-assisted (HA) fatigue crack growth (FCG) occurs in ferritic steels, wherein H-dislocation interaction plays a vital role. We aim to model the HAFCG mechanism based on the within the crack tip zone. Our modeling framework is as follows: H is condensed into crack tip and trapped by dislocations; these H significantly decrease dislocation mobility; stress relief via crack blunting is suppressed; localized brittle fracture triggers HAFCG.

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We introduce our proprietary Materials Informatics (MI) technologies and our chemistry-oriented methodology for exploring new inorganic functional materials. Using machine learning on crystal structure databases, we developed 'Element Reactivity Maps' that displays the presence or the predicted formation probability of compounds for combinations of 80 × 80 × 80 elements. By analysing atomic coordinates with Delaunay tetrahedral decomposition, we established the concept of Delaunay Chemistry.

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In this study, we investigate structural disorder and its implications in metal cluster (MC)-based compounds, specifically focusing on Cs[{MoX}X] (X = Cl and Br). Utilizing synchrotron radiation X-ray diffraction, Fourier transform infrared spectroscopy, and luminescence measurements, we examined the incorporation of water molecules into these compounds and their effects on the crystal structure and optical properties. Our findings reveal that the presence of water molecules induces the lattice disorder, particularly the displacement of Cs atoms.

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Role variability of surface chemistry and surface topography in anti-icing performance.

iScience

November 2024

Research Center for Macromolecules and Biomaterials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.

Largely varied anti-icing performance among superhydrophobic surfaces remains perplexing and challenging. Herein, the issue is elucidated by exploring the roles of surface chemistry and surface topography in anti-icing. Three superhydrophobic surfaces, i.

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Pyrrole in a cholesteric liquid crystal was discharged using a Tesla coil to generate pyrrole radicals, affording linear-shaped nano-ordered pyrrole oligomers. Subsequently, the electrochemical polymerisation of a pre-oriented pyrrole oligomer having good affinity for liquid crystals was performed to achieve polypyrrole-imprinted asymmetry from the cholesteric liquid crystal structure. The resultant polymers were analysed using polarising optical microscopy observations, scanning electron microscopy, electrochemistry, optical spectroscopy, and electron spin resonance.

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Although the Diels-Alder reaction (DA) has garnered significant attention due to its numerous advantages, its long reaction time is a drawback. Herein, we investigated the effects of polarity difference on DA using Layer-by-Layer (LbL) films comprising polycationic polyallylamine hydrochloride and polyanionic poly (styrenesulfonic acid-co-furfuryl methacrylate) [poly (SS--FMA)] as the reaction environment. First, furan composition in poly (SS--FMA) was adjusted to be 19 mol% to achieve good water solubility and layer deposition.

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Nanoscale light sources are demanded vigorously due to rapid development in photonic integrated circuits (PICs). III-V semiconductor nanowire (NW) lasers have manifested themselves as indispensable components in this field, associated with their extremely compact footprint and ultra-high optical gain within the 1D cavity. In this study, the carrier concentrations of indium phosphide (InP) NWs are actively controlled to modify their emissive properties at room temperature.

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Materials Nanoarchitectonics for Advanced Devices.

Materials (Basel)

December 2024

Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Ibaraki, Japan.

Advances in nanotechnology have made it possible to observe and evaluate structures down to the atomic and molecular level. The next step in the development of functional materials is to apply the knowledge of nanotechnology to materials sciences. This is the role of nanoarchitectonics, which is a concept of post-nanotechnology.

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ABO perovskite materials with small cations at the A site, especially with ordered cation arrangements, have attracted a lot of interest because they show unusual physical properties and deviations from general perovskite tendencies. In this work, A-site-ordered quadruple perovskites, RMnNiMnO with R = Nd, Sm, Gd, and Dy, were synthesized by a high-pressure, high-temperature method at about 6 GPa. Annealing at about 1500 K produced samples with additional (partial) B-site ordering of Ni and Mn cations, crystallizing in space group -3.

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Ameliorating Defects in Wide Bandgap Tin Perovskite Solar Cells Using Fluorinated Solvent and Hydrazide.

Small

December 2024

Photovoltaic Materials Group, Center for GREEN Research on Energy and Environmental Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.

Surface passivation with multifunctional molecules is an effective strategy to mitigate the defect and improve the performance and stability of perovskite solar cells (PSCs). Here, the fabrication of a wide bandgap-PSC is reported with tin perovskite (WB-Sn-HP; bandgap: 1.68 eV), followed by molecular surface passivation using 4-Fluoro-benzohydrazide (F-BHZ).

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Article Synopsis
  • Organic light-emitting diodes (OLEDs) seek to achieve near 100% quantum efficiency (QE) by utilizing excitons, but creating effective organic materials can be slow.
  • A new approach involves adding inorganic quantum dots, which serve as charge generation centers, to the organic luminescent layer, allowing unlimited exciton formation.
  • Using Silicon quantum dots (SiQDs), researchers showed significant improvements in external QE and electron transfer times, paving the way for wider applications across different colors and materials.
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Article Synopsis
  • Researchers developed a method to create metal-nitrogen-doped carbon single-atom catalysts (M-NC SACs) to improve the electrochemical reduction of CO, addressing challenges like metal aggregation.
  • They utilized ethylenediaminetetraacetic acid as a metal-chelating agent to prevent nickel nanoparticle formation, achieving a high loading of approximately 2.7 wt.%.
  • The resulting catalysts demonstrated impressive performance, with a CO faradaic efficiency of 96.6% and maintaining over 90% efficiency across a wide voltage range, due to an optimal local coordination structure that enhances catalytic activity.
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In biological systems, various stimuli and energies are transduced into membrane potentials via ion transport or binding. The application of this concept to artificial devices may result in biomimetic signal transmitters and energy harvesters. In this study, we investigated the mechanical control of fluoride anion recognition with naphthalenediimide (NDI) monolayers at the air-water interface.

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Solid-phase rare earth monoxides have been recently synthesized thin film epitaxy. However, it has been difficult to synthesize heavy rare earth monoxides owing to their severe chemical instability. In this study, rocksalt-type heavy rare earth monoxides REOs (RE = Tb, Dy, Er) were synthesized for the first time, as single-phase epitaxial thin films.

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2D materials such as transition metal dichalcogenides (TMDCs) are a new class of atomic-layer materials possessing optical and electric properties that significantly depend on the number of layers. Electronic transitions can be manipulated in artificial resonant electromagnetic (EM) fields using metasurfaces and other designed nanostructures. Here, we demonstrate prominently resonant enhancement in the photoluminescence (PL) of atomic monolayer, WS, doped with a small quantity of Mo.

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