A5101763501- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Perovskite Materials and Applications
- Organic Light-Emitting Diodes Research
- Semiconductor materials and devices
- Luminescence and Fluorescent Materials
- Molecular Junctions and Nanostructures
- Crystallization and Solubility Studies
- Solid-state spectroscopy and crystallography
- High Entropy Alloys Studies
- Advanced Memory and Neural Computing
- X-ray Diffraction in Crystallography
- Graphene research and applications
- Nonlinear Optical Materials Research
- Quantum Dots Synthesis And Properties
- Analytical Chemistry and Sensors
- Additive Manufacturing Materials and Processes
- Quantum and electron transport phenomena
- Fullerene Chemistry and Applications
- Chalcogenide Semiconductor Thin Films
- Synthesis and Properties of Aromatic Compounds
- Organoboron and organosilicon chemistry
- High Temperature Alloys and Creep
- Molecular Sensors and Ion Detection
- Electrochemical sensors and biosensors
Kyoto University
2015-2025
Kyoto Katsura Hospital
2024
Pohang University of Science and Technology
2017-2023
Center for Advanced Soft Electronics
2020
Osaka University
2014-2015
Graduate School USA
2014
Suita Municipal Hospital
2014
Abstract The excellent cryogenic tensile properties of the CrMnFeCoNi alloy are generally caused by deformation twinning, which is difficult to achieve at room temperature because insufficient stress for twinning. Here, we induced twinning improve alloy. Considering grain size effects on critical twins were readily formed in coarse microstructure cold rolling without refinement hot rolling. These retained partial recrystallization and played an important role improving strength, allowing...
Abstract We introduce a novel transformation-induced plasticity mechanism, i . e ., martensitic transformation from fcc phase to bcc phase, in medium-entropy alloys (MEAs). A VCrFeCoNi MEA system is designed by thermodynamic calculations consideration of stability between and phases. The resultantly formed martensite favorably contributes the plasticity, thereby leading significant enhancement both strength ductility as well strain hardening. reveal microstructural evolutions according Co-Ni...
Abstract Low dimensional (LD) perovskite materials generally exhibit superior chemical stability against ambient moisture and thermal stress than that of 3D perovskites. Recently, LD has been used as a passivation layer on the surface grains. Although various perovskites have developed focusing their hydrophobicity, impact crystal structure photovoltaic performance solar cell (PSC) is still uncertain. In this work, effects structural characteristics formation formamidinium lead triiodide...
Abstract A photomultiplication (PM)‐type organic photodetector (OPD) that exploits the ionic motion in CsPbI 3 perovskite quantum dots (QDs) is demonstrated. The device uses a QD monolayer as PM‐inducing interlayer and donor–acceptor bulk heterojunction (BHJ) layer photoactive layer. When illuminated, negative ions migrate accumulate near interface between QDs electrode; these processes induce hole injection from electrode yield PM phenomenon with an external efficiency (EQE) >2000% at V...
Abstract A novel photomultiplication (PM)‐type organic photodiode (OPD) that responds much faster (109 kHz bandwidth) than conventional PM‐type OPDs is demonstrated. This fast response achieved by introducing quantum dots (QDs) as a PM‐inducing interlayer at the interface between electrode and photoactive layer. When device illuminated, photogenerated electrons within layer are rapidly transferred trapped in trap states of QD interlayer. The electron trapping subsequently leads to charging...
ConspectusTwo-dimensional (2D) molecular materials, in which the major interactions are confined 2D planes with contrasted force fields acting between planes, have been key electronic functional materials since past decade. Even without referring to functionals of graphene-based systems, conjugated systems expected show extrawide dynamic ranges density states (DOS) tuning, effective electron mass, mobility, and conductivity. A advantage is their compatibility ubiquitous devices designed...
Independently stacked positively and negatively charged π-electronic systems in charge-segregated columnar structures are desired for electronic properties derived from their electron-deficient -rich assembling states, respectively. An expanded cation, benzoporphyrin AuIII complex, was synthesized as the component of ion pairs combination with counteranions. In contrast to benzoporphyrin, which is known its insolubility organic solvents, bulky anions this study soluble common solvents. The...
Organic semiconductors are usually polycyclic aromatic hydrocarbons and their analogs containing heteroatom substitution. Bioinspired materials chemistry of organic electronics promises new charge transport mechanism specific molecular recognition with biomolecules. We discover from deoxyribonucleic acid topoisomerase inhibitors, featuring conjugated backbone decorated hydrogen-bonding moieties distinct common semiconductors. Using ellipticine as a model compound, we find that hydrogen bonds...
We studied the charge-generation mechanism in low-bandgap polymer (P4TNTz-2F)-fullerene bulk heterojunction (BHJ) organic solar cells (OSCs) using transient absorption (TA) spectroscopy. The highly crystalline nanowire structure of P4TNTz-2F a blend film prepared with chlorobenzene (CB) and 1,8-diiodooctane (DIO) induced more long-lived charge carriers than those CB only. Pump-wavelength-dependent TA data revealed that increased charge-delocalization by intrachain ordering CB/DIO is key...
Abstract The relaxation time and mobility of electrons on graphene are deduced quantitatively by complex permittivity analysis with microwave dielectric loss spectroscopy. Hexagonal sheets uniform domain sizes from 6 to 30 µm, which target the mean free path based significantly longer turnover probing at gigahertz (GHz) frequencies as compared electrons, employed determine factors for carrier intradomain grain boundaries. changes in injections clearly show an evidence plasma carriers...
Because the metallophilicity of attractive Pt<sup>II</sup>⋯Pt<sup>II</sup> interactions helps in fabrication columnar structures, terpyridine–Pt<sup>II</sup> complexes were used as planar counter cationic species for formation charge-segregated assemblies using π-conjugated receptor–Cl<sup>−</sup> anions.
Pentagon-heptagon embedded polycyclic aromatic hydrocarbons (PAHs) have aroused increasing attention in recent years due to their unique physicochemical properties. Here, for the first time, this report demonstrates a facile method synthesis of novel B2 N2 -doped PAH (BN-2) containing two pairs pentagonal and heptagonal rings only steps. In solid state BN-2, different conformations, including saddle-shaped up-down geometries, are observed. Through combined spectroscopic calculation study,...
Despite dramatic improvements in the electronic characteristics of organic semiconductors, low operational stability field-effect transistors (OFETs) hinders their direct use practical applications. Although literature contains numerous reports on effects water OFETs, underlying mechanisms trap generation induced by remain unclear. Here, a protonation-induced semiconductors is proposed as possible origin instability transistors. Spectroscopic and investigation techniques combined with...
Abstract Photoinduced capacitances of perovskite solar cells exhibit peculiarities such as an apparently high capacitance and inductive feature, so‐called negative capacitance, which are not easily explained with typical carrier dynamics. Consequently, the origins photoinduced in have been intensively debated over past several years. Here, analyzed by impedance spectroscopy. The analysis clarifies that comprise Debye relaxation‐type components. Among these components, low‐frequency range is...
Organometal halide perovskite (OHP) solar cells have been intensively studied because of their promising optoelectronic features, which has resulted in high power conversion efficiencies >23 %. Although OHP exhibit efficiencies, relatively poor stability is a significant obstacle to practical use. We report that the chemical with respect both moisture and heat can be improved by adding small amount Ag precursor. doping increases size grains reduces amorphous intergranular regions at grain...
Abstract The gate voltage dependence of the charge carrier mobility is investigated by microwave resonance technique in transport channels at various organic semiconductors‐insulator interfaces. Although based measurement free from Schottky‐barrier, vertical transport, and minority trapping, which have been regarded as origin nonlinearity field effect transistor (FET) measurements, obtained impacted significantly applied bias. Atomic force microscopy (AFM) X‐ray diffractometry (XRD)...
Abstract Previous studies have reported contradictory effects of small-molecule acceptors on the environmental stability polymer:small-molecule blends, with one showing that a acceptor stabilizes and another it destabilizes polymer donor. In this work, to investigate origin these results, nanomorphologies blends are demonstrated. Investigations stabilities polymer:fullerene poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2- b :4,5-...
Abstract A series of donor–acceptor (D‐A) small molecules based on electron‐deficient benzothiadiazole (BTD) and electron‐rich benzodithiophene (BDT) featuring an A‐D‐A structure is presented. Exhaustive spectroscopic, electrochemical, computational studies evidence their electroactive nature ability to form well‐ordered thin films with broad visible absorptions low band gaps (ca. 2 eV). Time‐resolved microwave conductivity (TRMC) unveil unexpected n‐type charge transport displaying high...
Abstract The intrinsic, local-scale hole and electron mobilities at the interface between perylenediimide (PDI)-based liquid crystalline organic semiconductors insulating polymers were evaluated by field-induced time-resolved microwave conductivity (FI-TRMC). PDI crystals having alkyl semifluoroalkyl tails showed ambipolar of 0.2 0.3 cm2 V−1 s−1, respectively. In contrast, triethylene glycol no significant conductivity, suggesting an important role side chain structures on charge transport...
Charge carriers injected onto a graphene layer are perturbed by the probing microwave as rippling waves. By tracing these waves mass and mobility of electrons can be determined experimentally in technique referred Field-Induced Time-Resolved Microwave Conductivity (FI-TEMC) measurement, shown Shu Seki co-workers article number 1701402.
The temperature dependence of the anisotropic transient conductivity a La@C2v-C82(Ad) crystal was investigated using flash-photolysis time-resolved microwave (FP-TRMC) measurements. Results showed that along c-axis single-crystal increased as decreased, proving electron transport can be described by electronic band-conduction model instead electron-hopping model.