A5050211646- Advanced Condensed Matter Physics
- Organic Electronics and Photovoltaics
- Physics of Superconductivity and Magnetism
- Molecular Junctions and Nanostructures
- Electron and X-Ray Spectroscopy Techniques
- TiO2 Photocatalysis and Solar Cells
- Advanced Photocatalysis Techniques
- Magnetic and transport properties of perovskites and related materials
- Conducting polymers and applications
- Advanced Algebra and Geometry
- Multiferroics and related materials
- Perovskite Materials and Applications
- Algebraic Geometry and Number Theory
- Geology and Paleoclimatology Research
- Gas Sensing Nanomaterials and Sensors
- Organic and Molecular Conductors Research
- Copper-based nanomaterials and applications
- Advanced Chemical Physics Studies
- Advanced Thermoelectric Materials and Devices
- Economic theories and models
- Photochemistry and Electron Transfer Studies
- Chalcogenide Semiconductor Thin Films
- Transition Metal Oxide Nanomaterials
- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
Chiba University
2016-2025
Hokkaido University
2015-2024
Kyoto University
2007-2023
Chiba Institute of Technology
2011-2023
Robert Bosch (Germany)
2023
ITRI International
2006-2022
Nihon University
2004-2021
National Institute for Materials Science
2010-2021
Chiba Hospital
2018
Kansai Electric Power (Japan)
2000-2018
Jinmium rock shelter is famous for the claims made by Fullagar et al. (1996) early human colonization and ancient art of northern Australia. These were based on thermo‐luminescence ages obtained artefact‐bearing quartz sediments that form floor deposit at site. In this paper, we outline background to optical dating programme Jinmium, describe experimental design statistical methods used obtain from single grains sand. The results, interpretations, implications are reported in a companion...
The development of semiconducting polymers is imperative to improve the performance polymer-based solar cells (PSCs). In this study, new based on naphtho[1,2-c:5,6-c′]bis[1,2,5]thiadiazole (NTz), PNTz4TF2 and PNTz4TF4, having 3,3′-difluoro-2,2′-bithiophene 3,3′,4,4′-tetrafluoro-2,2′-bithiophene, respectively, are designed synthesized. These possess a deeper HOMO energy level than their counterpart, PNTz4T, which results in higher open-circuit voltages cells. This concequently reduces photon...
Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (spiro-OMeTAD). Conventional doping spiro-OMeTAD hygroscopic lithium salts and volatile 4-tert-butylpyridine is a time-consuming process also leads to poor device stability. We developed new strategy for that avoids post-oxidation by using stable radicals as dopant ionic modulator (referred...
Hole-collecting monolayers have drawn attention in perovskite solar cell research due to their ease of processing, high performance, and good durability. Since molecules the hole-collecting monolayer are typically composed functionalized π-conjugated structures, hole extraction is expected be more efficient when π-cores oriented face-on with respect adjacent surfaces. However, strategies for reliably controlling molecular orientation remain elusive. In this work, multiple phosphonic acid...
Electrochemical lithium intercalation into highly oriented pyrolytic graphite and natural powder was investigated using in situ Raman spectroscopy. Three plateaus were observed on the charging curve for both samples. From spectral changes first plateau assigned to a phase transition from dilute stage 1 4, second 2 another phase, third 1, which are good agreement with Dahn's results by x‐ray diffraction. The associated transitions occurred reversibly during charge discharge cycle. It shown of...
Quartz sediments from the floor deposit at Jinmium rock shelter have been investigated using multiple‐grain and single‐grain optical dating methods described by Galbraith et al. (1999, this volume). Here we present results of programme argue that artefact‐bearing were deposited within last 10000 years. This time interval is consistent with radiocarbon chronology but much younger than previous claims for initial human occupation during Pleistocene. Analysis individual grains revealed also...
A polycrystalline sample of vesignieite BaCu3V2O8(OH)2 comprising a nearly ideal kagome lattice composed Cu2+ ions carrying spin 1/2 has been synthesized and studied by magnetization heat capacity measurements. Magnetic susceptibility shows neither long range order, glass transition nor gap down to 2 K, in spite moderately strong antiferromagnetic interaction J/kB = 53 K between nearest-neighbor spins. broad peak observed at temperature corresponding 0.4J intrinsic magnetic indicates marked...
The structure of the thin film phase pentacene was investigated using x-ray diffraction reciprocal space mapping (RSM). crystal found to be triclinic with following lattice parameters: a=0.593nm, b=0.756nm, c=1.565nm, α=98.6°, β=93.3°, and γ=89.8°. Atomic positions were determined by comparing observed RSM intensities theoretical calculations.
Eliminating the excess energetic driving force in organic solar cells leads to a smaller energy loss and higher device performance; hence, it is vital understand relation between interfacial energetics photoelectric conversion efficiency. In this study, we systematically investigate 16 combinations of four donor polymers acceptors planar heterojunction. The charge generation efficiency its electric field dependence correlate with difference singlet excited state transfer state. threshold 0.2...
Ionization energy and electron affinity in organic solids are understood terms of a single molecule perturbed by solid-state effects such as polarization energy, band dispersion, molecular orientation primary factors. However, no work has been done to determine the individual contributions experimentally. In this work, affinities thin films pentacene perfluoropentacene with different orientations determined precision 0.1 eV using low-energy inverse photoemission spectroscopy. Based on...
A novel electron-deficient building unit, dithienylthienothiophenebisimide, and its polymers (PTBIs) are reported. Organic photovoltaic (OPV) cells based on PTBIs as p-type material exhibit 8.0% efficiencies with open-circuit voltages higher than 1 V. Interestingly, also function n-type in OPVs depending the molecular structure. These p-channel, n-channel, ambipolar behaviors field-effect transistors. As a service to our authors readers, this journal provides supporting information supplied...
The band gap of rutile TiO2 has been narrowed, via the formation oxygen vacancies (OVs) during heat treatment in carbon powder (cHT) with embedding coatings. narrowed efficiently improves visible light response coatings, to further enhance visible-light-driven photocatalytic activity. change OVs cHT studied by manipulation temperature and time. effect on structure nonstoichiometric TiO2-x calculated first-principles calculations. With raising temperature, SEM images show that nano-size...
Strongly bound excitons crucially affect the operation of organic optoelectronic devices. Nevertheless, precise experimental data on exciton binding energy semiconductors are lacking. In this study, we determine as difference between optical and transport bandgaps with a precision 0.1 eV. particular, electron affinities higher than 0.05 eV determined by low-energy inverse photoelectron spectroscopy allow us to gap energies such high precision. Through systematic comparison wide range...
High-performance and cost-effective hole-collecting materials (HCMs) are indispensable for commercially viable perovskite solar cells (PSCs). Here, we report an anchorable HCM composed of a triazatruxene core connected with three alkyl carboxylic acid groups (3CATAT-C3). In contrast to the phosphonic acid-containing tripodal analog (3PATAT-C3), 3CATAT-C3 molecules can form hydrophilic monolayer on transparent conducting oxide surface, which is beneficial subsequent film deposition in...
The electronic structure of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was studied using ultraviolet photoelectron spectroscopy vapor and thin film inverse photoemission film. threshold ionization energy PCBM found to be 7.17±0.04 eV in gas phase 5.96±0.02 solid phase. electron affinity 3.9±0.1 These values are 0.4−0.6 smaller than C60. density functional theory calculations gave consistent results with these trends suggested that the donation from side chain C60 backbone raised...