A5061282026- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Perovskite Materials and Applications
- Quantum and electron transport phenomena
- Solid-state spectroscopy and crystallography
- Semiconductor Quantum Structures and Devices
- Advanced Condensed Matter Physics
- Chalcogenide Semiconductor Thin Films
- Metal-Organic Frameworks: Synthesis and Applications
- Crystallography and molecular interactions
- Optical properties and cooling technologies in crystalline materials
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Multiferroics and related materials
- Organic and Molecular Conductors Research
- Magnetism in coordination complexes
- Advanced Semiconductor Detectors and Materials
- Magnetic properties of thin films
- Gas Sensing Nanomaterials and Sensors
- Catalysis and Oxidation Reactions
- Thermal Expansion and Ionic Conductivity
- Strong Light-Matter Interactions
- Quantum Dots Synthesis And Properties
- Covalent Organic Framework Applications
- Ga2O3 and related materials
Japan Synchrotron Radiation Research Institute
2020-2025
SPring-8
2021-2025
The University of Tokyo
1997-2023
Kindai University
2023
RIKEN Center for Emergent Matter Science
2023
Osaka University
2023
Hyogo University
2021
Fuji Machine (Japan)
2016
Tokyo University of Science
2002
National Defense Academy of Japan
2002
Abstract Quantum crystallography has become ever more important in recent years for the accurate determination of molecular and crystal structures. The results quantum crystallographic refinements X-ray data are as precise from neutron diffraction they give access to complete electronic structure compound under investigation. Is method now mature enough easy use extend ultimately supersede standard routines? We utilize world’s most common structure—the YLID test that every owner an...
The radiative decay of one-dimensional (1D) excitons is studied in novel GaAs quantum wires (QWI's) prepared by molecular beam epitaxy. temperature dependence the lifetime \ensuremath{\tau}(T) measured, and compared with that 2D wells (QW's): 1D grows much more slowly T than excitons, resulting shorter for T>20 K. This ascribed to thermalization concentrated density states QWIs. Analysis based on a theory has revealed expressed as 92\ensuremath{\surd}T ps...
Abstract We have measured the temperature dependence of reflection and photoluminescence spectra a lead bromide hybrid material (CH3NH3PbBr3) using high-quality macroscopic single crystals. Single crystals provide clear sample-independent that permit discussion properties photoexcited carriers. found excitons still exist in CH3NH3PbBr3, even at room temperature. also determined exciton resonance energy line width.
Transition-metal atoms with d electrons sometimes form clusters in crystals, which significantly affect the physical properties. Such a cluster formation frequently accompanies change crystal system, leading to presence of domains different orientations. In particular, cubic symmetry is rarely retained after formation. Here, we identify cubic-to-cubic phase transition lacunar spinel GaNb4Se8, where lattice parameter less than 0.0001%. Each Nb3.25+ tetramer seven 4d distorted into an Nb3+...
Metal halide perovskites are promising materials for light absorbers in solar cell applications. Use of the Br/I system enables us to control band gap energy and improves efficiency cells. Precise knowledge lattice parameters energies as functions compositions crucially important developing devices using those materials. In this study, we have determined CH3NH3Pb(I1–xBrx)3, one most intensively studied mix-halide perovskites, Br content x. We measured accurate contents CH3NH3Pb(I1–xBrx)3 (0...
Halide perovskite crystals are garnering significant interest as a promising material for next‐generation solar cells. They also anticipated to be applicable in devices used across wide temperature range, including X‐ray and γ‐ray detectors, well cells designed satellite environments. The coefficient of thermal expansion halide is critical physical property understand, especially given the potential mechanical degradation layered due abrupt fluctuations, which may result mismatched...
Recently, chiral semiconductors have attracted considerable attention owing to their potential applicability in optoelectronics and spintronics. In this study, homochiral heterochiral semiconductive Zn(II) coordination polymers [Zn(tbbt)((X)-mba)2]·solvent (H2tbbt = 4,4'-thiobisbenzenethiol, mba methylbenzylamine, X R, S, rac) were systematically synthesized. Single-crystal X-ray diffraction analyses revealed that KGF-57(R) KGF-57(S) (KGF Kwansei Gakuin framework), of type...
Among the thirty-two crystallographic point groups, 432 is only one that lacks an inversion center but does not exhibit piezoelectricity. A gyroidal structure belongs to group and shows characteristic physical properties attributed its distinctive strong isotropic network. Here, we investigate a cobalt oxalate metal-organic framework (MOF) with disordered orientations of SO4 tetrahedra. Synchrotron X-ray diffraction experiments using single crystal reveal cubic-to-cubic structural phase...
The peptide chain release factor 2 (RF2) gene, prfB, was cloned from Salmonella typhimurium by DNA hybridization using the Escherichia coli prfB probe. nucleotide and amino acid sequences of are 87.0% 95.6% homologous between E. S. typhimurium, respectively, including an in-frame premature UGA stop codon at position 26, site +1 frameshift for mature RF2 synthesis. supK584 mutation, which had been isolated as a recessive suppressor in caused opal (UGA) substitution 144 gene. Complementation,...
For the large-scale application of perovskite solar cells, it is crucial to improve their durability. However, this improvement limited because degradation mechanism under concurrent conditions, such as exposure light radiation and humidity, has not yet been clarified. Therefore, essential understand complicated process, which accelerated by a combination multiple factors. In study, we observed process in CH3NH3PbI3 crystals using situ 2D wide-angle X-ray scattering technique simultaneously...
Simultaneous control of noncentrosymmetry and spin-orbit-coupling strength has been demonstrated in a series chiral molecule-incorporated two-dimensional organic-inorganic hybrid perovskite copper halides (2D-OIHPs) with ferromagnetic exchange interaction. By substituting the halogen from Cl to Br, systematic change magnetic phase diagram simple complicated multiple phases observed. This is due competition between interaction Dzyaloshinskii-Moriya Materials design focusing on structural...
Abstract Mixed-stack complexes which comprise columns of alternating donors and acceptors are organic conductors with typically poor electrical conductivity because they either in a neutral or highly ionic state. This indicates that conductive carriers insufficient mainly localized. In this study, mixed-stack uniquely exist at the neutral–ionic boundary were synthesized by combining (bis(3,4-ethylenedichalcogenothiophene)) (fluorinated tetracyanoquinodimethanes) similar energy levels orbital...
Perovskite solar cells are efficient and cost-effective but have issues with ion migration from light irradiation. This study uses OHGaPc as a passivation layer to improve stability charge transport, increasing efficiency.
Lead halide perovskites are renowned for their exceptional optoelectronic properties but face concerns over lead toxicity and stability, which drives the exploration of lead-free perovskites, with Cs2AgBiBr6 standing out as a benchmark alternative. Understanding structural dynamics thermal transport is crucial remains an outstanding challenge due to complex atomic fluctuations. Here, through diffuse scattering experiments simulations, we uncover underlying dynamic local structure in...
An anomalously high valence state sometimes shows up in transition-metal oxide compounds. In such systems, holes tend to occupy mainly the ligand p orbitals, giving rise interesting physical properties as superconductivity cuprates and rich magnetic phases ferrates. However, no one has ever observed distribution of real space. Here, a successful observation spatial electrons cubic perovskite SrFeO3 by high-energy X-ray diffraction experiments precise electron density analysis using core...
Abstract We have measured photoluminescence spectra in CH 3 NH PbBr at low temperatures and found a nonlinear emission the lower energy side of exciton resonance. Considering that this signal shows rapid decay, we assigned it as originating from exciton–exciton inelastic scattering process called P-emission. The difference between P-emission free resonance is 20–30 meV, which consistent with recent studies binding energy.
2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (spiro-OMeTAD) is utilized as a p-type semiconductor layer in perovskite solar cells and solid-state dye-sensitized cells. Spiro-OMeTAD has been known to have spiro center, leading random orientation. Although the molecular orientation of organic materials influences conductivity, which directly related device characteristics, spiro-OMeTAD not fully discussed. In this study, we prepared layers on various substrates...
Hybrid lead halide perovskites typically form polycrystalline films that have multiple grain sizes and surface defects. A key engineering challenge toward commercialization is therefore the production of homogeneous, defect‐free large‐area devices achieving high efficiency. New market opportunities may arise from vacuum‐deposited if detailed understanding control crystal formation are available. Of many factors make reproducibility device performance difficult, two variables identified not...
Honeycomb-lattice antiferromagnets have attracted wide attention for exploration of exotic heat transport and their interplay with magnetic excitations.In this work, we revealed a contrasting behavior in the magneto-thermal conductivity (MTC) between two Co-based honeycomb-lattice magnets Co4M2O9 (M = Nb, Ta), despite identical lattice structures quite similar magnetism.Co4Ta2O9 exhibits enhanced MTC about 550 % at 9 T an in-plane field, comparable to other honeycomb-magnets, while Co4Nb2O9...
Perovskite solar cells are actively investigated for their potential as highly efficient and cost-effective photovoltaic devices. However, a significant challenge in practical application is enhancing durability. Particularly, these expected to be subjected heating by sunlight real-world operating environments. Therefore, high-temperature durability device operation under such conditions critical. Our study aims improve the of perovskite applications examining temperature coefficients at...
Recent advent of diverse chemical entities necessitates a re-evaluation bond concepts, underscoring the importance experimental evidence. Our prior study introduced general methodology, termed Core Differential Fourier Synthesis (CDFS), for mapping distribution valence electron density (VED) in crystalline substances within real space. In this study, we directly compare VED distributions obtained through CDFS with those derived from high-accuracy theoretical calculation using long-range...
Abstract The development of molecular switches with tunable properties has garnered considerable interest over several decades. A novel spin‐crossover ( SCO ) material based on iron(II) complexes incorporating 4‐acetylpyridine (4‐acpy) and [Hg(SCN) 4 ] 2− anions was synthesized formulated as [Fe(4‐acpy) 2 ][Hg( μ ‐SCN) 1 ). Compound is crystallized in a three‐dimensional network the non‐centrosymmetric orthorhombic space group Pna two octahedral (NCS) entities featuring distinct Fe centers...