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Your search keyword '"Imazu, Naoki"' showing total 19 results
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19 results on '"Imazu, Naoki"'

3. Fabrication of Highly Transparent, Thermally Stable, and Scalable Conductive Films from Double-Walled Carbon Nanotubes

Author

Imazu Naoki, Naotoshi Nakashima, and Tsuyohiko Fujigaya

Subjects
Fabrication, business.industry, Annealing (metallurgy), Chemistry, General Chemistry, Carbon nanotube, Conductivity, law.invention, law, Optoelectronics, Thermal stability, Electronics, business, Electrical conductor, Transparent conducting film
Abstract

To fabricate transparent conducting films (TCFs) for electronic devices, both a high conductivity and thermal stability are significant issues due to the need for a high temperature annealing proce...

Published
2015
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4. Morphology and melting behavior of ionic liquids inside single-walled carbon nanotubes

Author

Shimou Chen, Kobayashi, Keita, Miyata, Yasumitsu, Imazu, Naoki, Saito, Takeshi, Kitaura, Ryo, and Shinohara, Hisanori

Subjects
Ammonium chloride -- Chemical properties, Ammonium chloride -- Structure, Ammonium chloride -- Thermal properties, Ammonium compounds -- Chemical properties, Ammonium compounds -- Structure, Ammonium compounds -- Thermal properties, Ammonium paratungstate -- Chemical properties, Ammonium paratungstate -- Structure, Ammonium paratungstate -- Thermal properties, Ionic solutions -- Chemical properties, Nanotubes -- Structure, Nanotubes -- Chemical properties, Zinc -- Chemical properties, Chemistry
Abstract

The synthesis and characterization of single-walled carbon nanotubes (SWNTs) filled with a zinc-containing quaternary ammonium based ionic liquid (ChZnCl3) inside is reported. The versatility of ionic liquids and the unique phase transition observed inside the SWNTs provide a new opportunity for modulation of the electronic properties of carbon nanotubes.

Published
2009

6. Highly air- and moisture-stable hole-doped carbon nanotube films achieved using boron-based oxidant

Author

Taishi Takenobu, Yoshiaki Shoji, Imazu Naoki, Hiromichi Ohta, Kaito Kanahashi, Hiroyuki Shirae, Ko Nakayama, Naoki Tanaka, Suguru Noda, Takanori Fukushima, and Kazuma Funahashi

Subjects
Nanotube, Materials science, General Physics and Astronomy, Salt (chemistry), chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, law.invention, Condensed Matter::Materials Science, law, Condensed Matter::Superconductivity, Relative humidity, Boron, Physics::Atmospheric and Oceanic Physics, chemistry.chemical_classification, Moisture, Doping, General Engineering, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Chemical engineering, Reagent, 0210 nano-technology
Abstract

Hole doping into carbon nanotubes can be achieved. However, the doped nanotubes usually suffer from the lack of air and moisture stability, thus, they eventually lose their improved electrical properties. Here, we report that a salt of the two-coordinate boron cation Mes2B+ (Mes: 2,4,6-trimethylphenyl group) can serve as an efficient hole-doping reagent to produce nanotubes with markedly high stability in the presence of air and moisture. Upon doping, the resistances of the nanotubes decreased, and these states were maintained for one month in air. The hole-doped nanotube films showed a minimal increase in resistance even upon humidification with a relative humidity of 90%.

Published
2017

7. Fabrication of flexible transparent conductive films from long double-walled carbon nanotubes

Author

Tsuyohiko Fujigaya, Naotoshi Nakashima, and Imazu Naoki

Subjects
Fabrication, Materials science, lcsh:Biotechnology, Carbon nanotube, engineering.material, law.invention, Flexible transparent conducting film, Supramolecular material, Coating, law, lcsh:TP248.13-248.65, Transmittance, lcsh:TA401-492, General Materials Science, Composite material, Electrical conductor, Transparent conducting film, chemistry.chemical_classification, Doping, Polymer, chemistry, Papers, engineering, Flexible device material, lcsh:Materials of engineering and construction. Mechanics of materials
Abstract

The fabrication of flexible transparent conducting films (TCFs) is important for the development of the next-generation flexible devices. In this study, we used double-walled carbon nanotubes (DWCNTs) as the starting material and described a fabrication method of flexible TCFs. We have determined in a quantitative way that the key factors are the length and the dispersion states of the DWCNTs as well as the weight-ratios of dispersant polymer/DWCNTs. By controlling such factors, we have readily fabricated a flexible highly transparent (94% transmittance) and conductive (surface resistivity = 320 Ω sq-1) DWCNT film without adding any chemical doping that is often used to reduce the surface resistivity. By applying a wet coating, we have succeeded in the fabrication of large-scale conducting transparent DWCNT films based on the role-to-role method.

Published
2014

15. Element-Specific Magnetic Properties of Di-Erbium Er2@C82 and Er2C2@C82 Metallofullerenes: A Synchrotron Soft X-ray Magnetic Circular Dichroism Study

Author

Okimoto, Haruya, primary, Kitaura, Ryo, additional, Nakamura, Tetsuya, additional, Ito, Yasuhiro, additional, Kitamura, Yutaka, additional, Akachi, Takao, additional, Ogawa, Daisuke, additional, Imazu, Naoki, additional, Kato, Yuko, additional, Asada, Yuki, additional, Sugai, Toshiki, additional, Osawa, Hitoshi, additional, Matsushita, Tomohiro, additional, Muro, Takayuki, additional, and Shinohara, Hisanori, additional

Published
2008
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16. STM and STS Studies on the Density of States Modulation of Pr@C82and Sc3C2@C80Binary-Metallofullerene Peapods

Author

Iijima, Yuki, Ohashi, Kazunori, Imazu, Naoki, Kitaura, Ryo, Kanazawa, Ken, Taninaka, Atsushi, Takeuchi, Osamu, Shigekawa, Hidemi, and Shinohara, Hisanori

Abstract

The density of states modulation of single-wall carbon nanotubes (SWCNTs) is induced by the encapsulation of two different kinds of metallofullerenes (Pr@C82and Sc3C2@C80). We report the observation of the modulated density of states using scanning tunneling microscopy/spectroscopy, where the modulation is successfully reproduced by density functional theory calculation. The metallofullerene molecules in SWCNTs strongly affect the local band structures of SWCNTs. The present findings show that the local electronic structures of SWCNTs can be modified by not only varying the geometric structures of SWCNTs but also the varieties of metallofullerenes encapsulated.

Published
2013
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17. Element-Specific Magnetic Properties of Di-Erbium Er2C82and Er2C2C82Metallofullerenes:  A Synchrotron Soft X-ray Magnetic Circular Dichroism Study

Author

Okimoto, Haruya, Kitaura, Ryo, Nakamura, Tetsuya, Ito, Yasuhiro, Kitamura, Yutaka, Akachi, Takao, Ogawa, Daisuke, Imazu, Naoki, Kato, Yuko, Asada, Yuki, Sugai, Toshiki, Osawa, Hitoshi, Matsushita, Tomohiro, Muro, Takayuki, and Shinohara, Hisanori

Abstract

The magnetic properties of mono- and dierbium(Er) metallofullerenes have been studied by means of a synchrotron soft X-ray magnetic circular dichroism (SXMCD) technique. The effective magnetic moment of the Er ions has been estimated to be 8.48 Band is independent of the number of Er ions encapsulated inside the fullerene cage. These Er metallofullerenes exhibit an antiferromagnetic-like behavior at low temperatures that is stronger in ErC82(C2visomer) monometallofullerene than in Er2C82(C2v) and Er2C2C82(C2v) dimetallofullerenes. The result suggests that the unpaired spin on the monometallofullerene cages causes an indirect magnetic interaction between Er 4f spins of neighboring metallofullerenes. Furthermore, we have found that the Weiss temperatures of the metallofullerene remain the same even when one of the Er ions in Er2C2C82(Cs) is replaced by a nonmagnetic Y ion (i.e., ErYC2C82). The results indicate that interaction between the two Er ions in the same fullerene cage does not contribute significantly to the overall magnetic properties.

Published
2008
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19. Fabrication of metal nanowires in carbon nanotubes via versatile nano-template reaction.

Author

Kitaura R, Imazu N, Kobayashi K, and Shinohara H

Subjects
Macromolecular Substances chemistry, Materials Testing, Molecular Conformation, Particle Size, Surface Properties, Crystallization methods, Metals chemistry, Nanotechnology methods, Nanotubes, Carbon chemistry, Nanotubes, Carbon ultrastructure
Abstract

A nano-template reaction has been developed to fabricate metal nanowires using metallofullerene nanopeapods (i.e., carbon nanotubes (CNTs) encapsulating endohedral metallofullerenes) as starting materials. In this nanometer-scale reaction, the structure of resulting products should possess specific low-dimensional structures, because of their uniform starting orientation of metallofullerene molecules and the rigid restriction of reaction space by the presence of walls of CNTs. Using the nano-template reaction, we have fabricated various Gd nanowires, including a single Gd atomic chain, a one-dimensional alignment of Gd squares, and Gd nanowires that correspond to a one-dimensional segment of the bulk close-packed structure. The same reaction, in principle, can be applied to fabricate more than 20 different types of metal nanowires in the CNTs, which simply are dependent on the use of the corresponding different types of metallofullerenes as encapsulates in the CNTs. The present novel reaction will provide a wide variety of unusual low-dimensional nanowires and nanomaterials in the CNTs, which have not been synthesized via the fabrication techniques that have been reported so far.

Published
2008
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