A5041730786- Carbon Nanotubes in Composites
- Graphene research and applications
- Polydiacetylene-based materials and applications
- Diamond and Carbon-based Materials Research
- Glass properties and applications
- Organic and Molecular Conductors Research
- Ion-surface interactions and analysis
- Photoreceptor and optogenetics research
- Luminescence Properties of Advanced Materials
- Semiconductor materials and devices
- Solid-state spectroscopy and crystallography
- Magnetism in coordination complexes
- Silicon Nanostructures and Photoluminescence
- Phase-change materials and chalcogenides
- Spectroscopy and Quantum Chemical Studies
- Synthesis and Properties of Aromatic Compounds
- Thin-Film Transistor Technologies
- Electronic and Structural Properties of Oxides
- Supramolecular Self-Assembly in Materials
- Transition Metal Oxide Nanomaterials
- Photopolymerization techniques and applications
- Photochromic and Fluorescence Chemistry
- Catalytic Processes in Materials Science
- Carbon dioxide utilization in catalysis
- Advanced Chemical Physics Studies
Wakayama University
2010-2020
Kitasato University
2016
Kitasato Institute Hospital
2010
Nagoya University
1986-2001
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
1998
CEA Paris-Saclay
1998
Linear polarisation, with respect to the z axis, and effect of subsequent laser-induced excitation on luminescence transient optical absorption induced by irradiation crystalline SiO2 an electron pulse have been studied. It is found that spectrum consists two bands peaked at 2.8 eV 2.5 transition dipole moment former, which has shown be intrinsic, nearly parallel while latter x axis. In addition 5.2 band, a satellite band 4.2 pulse. For both these bands, dipoles are not any axes. Subsequent...
Luminescence and optical absorption induced by an electron pulse a subsequent laser have been studied in densified undensified amorphous Si${\mathrm{O}}_{2}$ at 77 K. We find that the decay of optical-absorption change consists two components: one which decays following power law within 1 ms other much more slowly. The fast component exhibits spectrum self-trapped excitons, while slow includes ${E}^{\ensuremath{'}}$ band. band thus generated is found to with time constant about 10 h K be...
The excitation spectrum of the 2.8-eV luminescence band crystalline Si${\mathrm{O}}_{2}$ has been measured in a photon energy range between 6 and 14 eV at 77 K. We find that onset occurs 8.3 eV, which is nearly equal to fundamental optical absorption edge Si${\mathrm{O}}_{2}$. This result supports strongly model due radiative recombination self-trapped excitons.
The transient optical absorption and luminescence induced by irradiation of amorphous SiO2 with an electron pulse have been measured. It is found that the spectra do not depend on impurities a strong peak at 5.3 eV satellite 4.2 eV. energy band to show blue shift as time after increases. By means cascade excitation experiment, eV, shown arise from same centre, which ascribed self-trapped exciton or metastable excited state accompanied large lattice distortion.
A two-dimensional nanocarbon, graphene, has attracted substantial interest due to its excellent properties. The reduction of graphene oxide (GO) been investigated for the mass production used in practical applications. Different processes produce different properties affecting performance final materials or devices. Therefore, an understanding mechanisms GO is important controlling functional systems. Here, we determined average structure reduced prepared via heating and photoexcitation...
Interfaces in nanocarbon materials are highly important, as they determine the properties of carbon-based devices. In terms carrier and thermal transport properties, interfacial features often more important than intrinsic characteristics. Herein, we describe how 1 min Joule annealing carbon nanotube (CNT) yarns can convert amorphous into graphene fragments. After annealing, have obtained multiwalled CNT with extremely high Seebeck coefficients (±100 μV/K) thermoelectric power factor (400...
We comprehensively analyzed X-ray cocrystal structures of dipeptidyl peptidase IV (DPP-4) and its inhibitor to clarify whether DPP-4 alters general or partial structure according the used has a common rule for binding.All main side chains in binding area were minimally altered, except few chains, despite inhibitors various shapes. Some residues (Arg125, Glu205, Glu206, Tyr662 Asn710) had modes fix specific atom particular spatial position DPP-4. found two water molecules that 92 structures....
Abstract Photocurrent of lead tungstate (PbWO 4 ) single crystals has been studied in the temperature range from K to 270 K. The excitation spectrum photocurrent characterized by a prominent peak at 4.1 eV and rise above 4.5 was obtained Below 150 K, photocurrents excited 4.15 4.7 show analogous dependence with each others. However, exhibits thermal activation type We find that showing is induced efficiently 4.12 eV, but neither excitonic transition nor band‐to‐band transition. discussed...
X-ray induced defects in single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were characterized by Raman scattering spectroscopy. Frenkel defects, interstitial-vacancy pairs, revealed to form both SWCNTs DWCNTs after irradiation because these entirely healed thermal annealing. In order clarify the structure of defect SWCNT DWCNT, isochronal-annealing experiments performed on irradiated samples activation energy for healing was estimated. The intensity D band (defect band)...
Transient volume change induced by irradiation with an electron pulse of alpha -Al2O3 and Cr doped Al2O3 have been measured above 77K. It is found that the in shows a single exponential decay lifetime 12 ms below 140K initial value linear function fluence not influenced doping Cr3+. suggested transient observed associated relaxed excited state resulting from fundamental electronic excitation, possibly self-trapped exciton.
Relaxation of photo-generated carriers in anatase form crystalline titanium dioxide has ben studied by the photoconductivity measurement. Illumination crystal with UV light at 300 K found to induce persistent enhancement conductivity over 3000 seconds. The magnitude induced change is 4000 times greater than that measured rutile same experimental condition. decay after termination illumination was characterized stretched exponential function. excitation spectrum measurement revealed...
The formation of X-ray-induced defects changes the spectral shape radial breathing mode (RBM) and defect-induced (D band) in Raman spectra single-walled carbon nanotubes (SWNTs). have been found to be annealed by thermal treatment, indicating that they are Frenkel pairs (vacancy interstitial pairs). We RBM is not entirely recovered after post-irradiation annealing. temperatures for complete annealing were within range 200–600 °C depending on tube geometry. From these results, we suggest...
Abstract We have studied Fourier‐transform IR‐reflection spectra of tetrathiafulvalene‐ p ‐chloranil (TTF‐CA) crystal under continuous excitation by 532‐nm laser beam at 6 K. The the with power ( P ) 6.1 Wcm –2 induces an enhancement around 1640 cm –1 , which is ascribed to carbonyl stretching vibration CA molecules in neutral phase. Meanwhile, moderate < 3.5 gives intensity charge‐transfer (CT) reflection and a reduction g ‐mode band but no change band. results show that there threshold...
We have found that a Raman scattering (RS) peak around 1870 cm−1 was produced by the annealing of X-ray irradiated film single-walled carbon nanotubes (SWNTs) at 450 oC. The intensity 1870-cm−1 showed maximum probe energy 2.3 eV for RS spectroscopy with various lasers. Both position and probe-energy dependence were almost identical to those one-dimensional chains previously reported in multi-walled nanotubes. Consequently, we concluded present study is attributed chains. formation...
Modification by electronic excitation of semiconductor surfaces and carbon-related quasi-two-dimensional (2D) nanostructured materials, namely graphene, carbon nanotubes is reviewed. Defect creation in these materials takes place not low-intensity photoirradiation, but laser or electron irradiation. The defect processes are different from ordinary photochemical molecules some solids like alkali halides, which can be modified a localized exciton. It pointed out that there common features...
Diameter-dependent annealing effects of X-ray-induced defects in single-walled carbon nanotubes (SWNTs) were studied by Raman scattering spectroscopy. We found that X- ray-induced formed thin SWNTs at higher density than thick SWNTs. The defects, distant pairs interstitials and vacancies (I-V), eliminated thermal annealing. recovery temperature the ones, indicating stability thinner are higher. In order to simulate behaviours with diameters ∼0.9 ∼1.4 nm, we suggested competitive reactions...
Optical absorption changes induced by 308-nm laser pulses and electron at low temperatures were studied for crystalline 5,7-dodecadiyne-1,12-diol bis[phenylcarbamate](TCDU; R-C≡C-C≡C-R, R=(CH 2 ) 4 O(CO)C 6 H 5 ). The dimer diradical which shows an band 3.05 eV is not formed the electron-pulse irradiation, but efficiently irradiation with pulses. By exciting crystals pulse a sequentially, it shown that collision of excited species lowest triplet state crucial step in generating diradical....