Faculty Profiles - AKIYAMA Tsuyoshi

Papers - AKIYAMA Tsuyoshi

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A Z-scheme type photoelectrochemical cell consisting of porphyrin-containing polymer and dye-sensitized TiO2 electrodes "jointly worked" Reviewed

Kensuke Takechi, Tohru Shiga, Tsuyoshi Akiyama, Sunao Yamada

Photochemical & Photobiological Sciences 9 1085 - 1087 2010.8

Selective formation and structural properties of rhombic dodecahedral [70]fullerene microparticles formed by reaction with aliphatic diamines Reviewed

Matsuoka K.I., Akiyama T., Yamada S.

Langmuir 26 ( 6 ) 4274 - 4280 2010.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Langmuir

We have accomplished the selective formation of rhombic dodecahedral microparticles on the submicrometer to micrometer scale by the reaction of [70]fullerene (C ) with primary aliphatic diamines. The morphology of the resultant microparticles was analyzed by scanning electron microscopy, powder X-ray diffraction, and other spectroscopic methods, demonstrating that the resultant particles held a rhombic dodecahedral shape having a simple cubic lattice structure and that primary aliphatic amines were mostly trapped inside the particles through electronic interaction between C and amines. Furthermore, we have discovered interesting structural characteristics in which the incorporated amines could be removed from the C microparticles or exchanged with other primary aliphatic diamines. © 2010 American Chemical Society. 70 70 70

DOI： 10.1021/la903355e

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Selective Formation and Structural Properties of Rhombic Dodecahedral [70]Fullerene Microparticles Formed by the Reaction with Aliphatic Diamines（共著） Reviewed

Matsuoka, Ken-ichi; Akiyama, Tsuyoshi*; Yamada, Sunao*.

Langmuir 26 4274 - 4280 2010.3

A Z-scheme type photoelectrochemical cell consisting of porphyrin-containing polymer and dye-sensitized TiO<inf>2</inf> electrodes Reviewed

Takechi K., Shiga T., Akiyama T., Yamada S.

Photochemical and Photobiological Sciences 9 ( 8 ) 1085 - 1087 2010.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Photochemical and Photobiological Sciences

A Z-scheme type photoelectrochemical cell consisting of an electrochemically polymerized photoactive electrode and a dye-sensitized TiO electrode is demonstrated. Nearly 1 V of open circuit voltage (V ) was achieved by the cooperation of a couple of photoactive electrodes toward uphill electron pumping. © 2010 The Royal Society of Chemistry and Owner Societies. 2 OC

DOI： 10.1039/c0pp00086h

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Enormous enhancement in photocurrent generation using electrochemically fabricated gold nanostructures Reviewed

Akiyama T., Aiba K., Hoashi K., Wang M., Sugawa K., Yamada S.

Chemical Communications 46 ( 2 ) 306 - 308 2010.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Communications

A self-assembled monolayer of porphyrins fabricated on the surface of an electrochemically deposited gold nanostructure exhibits enormous enhancement of photocurrent due to porphyrin excitation, especially in the near-infrared region, where localized surface plasmon resonance was responsible. © 2010 The Royal Society of Chemistry.

DOI： 10.1039/b913284h

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Enormous Enhancement in Photocurrent Generation Using Electrochemically Fabricated Gold Nanostructures（共著） Reviewed

Akiyama, Tsuyoshi*; Aiba, Kenta; Hoashi, Kazuko; Wang, Meng; Sugawa, Kosuke; Yamada, Sunao.

Chemical Communications 46 306 - 308 2010.1

Enhanced absorption and emission in a copper phthalocyanine-gold nanoparticle system assisted by localized surface plasmon Reviewed

Sugawa K., Kawahara T., Akiyama T., Kobayashi M., Takahara A., Yamada S.

Chemistry Letters 38 ( 4 ) 326 - 327 2009.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemistry Letters

Localized surface plasmon resonance leads to an increase in the degree of photon absorption and concomitant emission in copper phthalocyanine-gold nanoparticle systems. Copyright © 2009 The Chemical Society of Japan.

DOI： 10.1246/cl.2009.326

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Effects of silver nanoparticles on photoelectrochemical responses of organic dyes Reviewed

Arakawa T., Munaoka T., Akiyama T., Yamada S.

Journal of Physical Chemistry C 113 ( 27 ) 11830 - 11835 2009.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Physical Chemistry C

The electrostatic layer-by-layer adsorption technique was used to fabricate silver nanoparticle (AgP)-organic dye composite films on indium-tin-oxide (ITO) electrodes. The degree of immobilization for the AgPs on the ITO electrode could be controlled by changing the immersion time of the electrode in the AgP aqueous colloidal solution. Porphyrin and phthalocyanine were selected as the dye molecules here because the former has a strong absorption band around the plasmon band of isolated AgPs, while the latter has one around the plasmon band of aggregated AgPs (interparticle plasmon coupling). Remarkable enhancement in the photocurrent action and fluorescence excitation spectra was observed for both dyes when considerable amounts of AgPs were deposited onto the ITO electrode. The Raman scattering measurements suggested the effects of enhanced electric fields resulting from localized surface plasmon resonance and light scattering on the photocurrent enhancement. © 2009 American Chemical Society.

DOI： 10.1021/jp9018525

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Effects of Silver Nanoparticles on Photoelectrochemical Responses of Organic Dyes Arakawa, Taichi; Munaoka, Takatoshi; Akiyama, Tsuyoshi; Yamada, Sunao. （共著） Reviewed

Arakawa, Taichi; Munaoka, Takatoshi; Akiyama, Tsuyoshi; Yamada, Sunao.

The Journal of Physical Chesmitry C 113 11830 - 11835 2009.6

Photocurrent generation properties of electrochemically polymerized terthiophene-linked fullerene film Reviewed

Akiyama T., Fukuyama T., Sugawa K., Yoneda H., Yamada S.

Synthetic Metals 159 ( 9-10 ) 965 - 968 2009.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Synthetic Metals

Terthiophene derivative of C fullerene was synthesized. The polymerized film of this fullerene analog was prepared on an indium-tin-oxide electrode by electrochemical polymerization at +1.4 V versus a Ag wire. The absorbance of the polymerized film was increased by increasing the electrochemical polymerization time. The polymerized film generated stable photocurrents in the presence of triethanolamine. Optimization of the amount of adsorbed polymerized film for improving the photoelectric conversion performance was achieved by controlling the polymerization time. © 2009 Elsevier B.V. All rights reserved. 60

DOI： 10.1016/j.synthmet.2009.02.019

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Facile fabrication and photocurrent generation properties of electrochemically polymerized fullerene-poly(ethylene dioxythiophene) composite films Reviewed

Akiyama T., Yoneda H., Fukuyama T., Sugawa K., Yamada S., Takechi K., Shiga T., Motohiro T., Nakayama H., Kohama K.

Japanese Journal of Applied Physics 48 ( 4 PART 2 ) 2009.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics

Fullerene-poly(ethylene dioxythiophene) (polyEDOT) composite films consisting of 3,4-ethyeledioxythiophene (EDOT) and a thiophene derivative of C fullerene (ThC ) or C fullerene were fabricated on a transparent indium-tin-oxide (ITO) electrode by electrochemical polymerization of the electrolyte solution of ThC (or C ) and EDOT. Incorporation of the C fullerene moiety in the polythiophene film was strongly suggested from absorption spectra of the composite film. We have found a higher degree of incorporation of the C fullerene moiety into the ThC -polyEDOT film, as compared with the C -polyEDOT film. In the presence of methylviologen as an electron acceptor, the as-prepared C -polyEDOT and ThC -polyEDOT composite films generated stable cathodic photocurrents in the 400-700nm region with broad peaks. The photocurrent intensity and the internal photon-to-current quantum efficiency of the ThC -polyEDOT composite film were considerably larger than those of C -polyEDOT and polyEDOT films. The thiophene unit of ThC was confirmed to be quite effective for a stable incorporation of the C fullerene moiety in the film and a higher photocurrent generation. © 2009 The Japan Society of Applied Physics. 60 60 60 60 60 60 60 60 60 60 60 60 60 60 60

DOI： 10.1143/JJAP.48.04C172

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Structural characterization and photoelectrochemical properties of gold nanoparticle multistructures prepared by layer-by-layer deposition Reviewed

Sugawa K., Kawahara T., Akiyama T., Yamada S.

Japanese Journal of Applied Physics 48 ( 4 PART 2 ) 2009.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics

Surface plasmon, which is induced by the oscillation of free electrons at the surface of a metal, generates remarkable enhancement of localized electric field owing to its interaction with the incident light field, which is called localized surface plasmon resonance (LSPR). In this study, we have fabricated densely packed multistructures of gold nanoparticle films by a layer-by-layer approach using polyions and films of LSPR-active gold nanoparticles prepared at the liquid-liquid interface. The structure and the optical properties of the multistructure were evaluated by transmission absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and quartz crystal microbalance (QCM) measurements. In addition, the photoelectrochemical investigations of these films verified the anodic photocurrent generation due to photoexcitation of the gold nanoparticles. © 2009 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.48.04C132

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Structural Characterization and Photoelectrochemical Properties of Gold Nanoparticle Multistructures Prepared by Layer-by-Layer Deposition （共著） Reviewed

Sugawa, Kosuke; Kawahara, Tomoaki; Akiyama, Tsuyoshi; Kobayashi, Motoyasu; Takahara, Atsushi; Yamada, Sunao*.

Japanese Journal of Applied Physics 48 04C132(1) - 04C132(5) 2009.4

Facile Fabrication and Photocurrent Generation Properties of Electrochemically Polymerized Fullerene-Poly(ethylene dioxythiophene) Composite Films（共著） Reviewed

Akiyama, Tsuyoshi*; Yoneda, Hiroyuki; Fukuyama, Toshihide; Sugawa, Kosuke; Yamada, Sunao; Takechi, Kensuke; Shiga, Tohru; Motohiro, Tomoyoshi; Nakayama, Hideki; Kohama, Keiichi.

Japanese Journal of Applied Physics 48 04C172(1) - 04C172(4) 2009.4

Photocurrent generation properties of electrochemically polymerized terthiophene-linked fullerene film（共著） Reviewed

Akiyama, Tsuyoshi*; Fukuyama, Toshihide; Sugawa, Kosuke; Yoneda, Hiroyuki; Yamada, Sunao.

Synthetic Metals 159 965 - 968 2009.4

Plasmon-enhanced photocurrent generation from self-assembled monolayers of phthalocyanine by using gold nanoparticle films Reviewed

Sugawa K., Akiyama T., Kawazumi H., Yamada S.

Langmuir 25 ( 6 ) 3887 - 3893 2009.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Langmuir

The effect of localized electric fields on the photocurrent responses of phthalocyanine that was self-assembled on a gold nanoparticle film was investigated by comparing the conventional and the total internal reflection (TIR) experimental systems. In the case of photocurrent measurements, self-assembled monolayers (SAMs) of a thiol derivative of palladium phthalocyanine (PdPc) were prepared on the surface of gold-nanoparticle film that was fixed on the surface of indium-tin-oxide (ITO) substrate via a polyion (PdPc/AuP/polyion/ITO) or on the ITO surface (PdPc/ITO). Photocurrent action spectra from the two samples were compared by using the conventional spectrometer, and were found that PdPc/AuP/polyion/ITO gave considerably larger photocurrent signals than PdPc/ITO under the identical concentration of PdPc. In the case of the TIR experiments for the PdPc/AuP/polyion/ITO and the PdPc/AuP/Glass systems, incident-angle profiles of photocurrent and emission signals were correlated with each other, and they were different from that of the PdPc/ITO system. Accordingly, it was demonstrated that the photocurrent signals were certainly enhanced by the localized electric fields of the gold-nanoparticle film. © 2009 American Chemical Society.

DOI： 10.1021/la803831c

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Characterization of copper phthalocyanine nanoparticles formed by laser ablation in poor solvents Reviewed

Leonard K., Tun M.T., Kurawaki J., Akiyama T., Yamada S.

e-Journal of Surface Science and Nanotechnology 6 312 - 316 2008.12

Language：English Publishing type：Research paper (scientific journal) Publisher：e-Journal of Surface Science and Nanotechnology

Laser irradiation of Copper phthalocyanine tetrasulfonate (CuPcTs) microcrystals in some poor solvents has produced CuPcTs nanoparticles with 15-112 nm in diameter. Field emission scanning electron microscopy (FESEM) images have shown densely packed nanoparticles of CuPcTs formed in methanol and acetone. The mean diameter of CuPcTs nanoparticles obtained from TEM images in methanol, 2-methy-2-propanol, ethanol, tetrahydrofuran, and acetone were determined to be 26, 36, 35, 86, and 78 nm, respectively. The size and surface morphology of CuPcTs nanoparticles have been correlated with solvent parameters such as polarity and thermal diffusivity. © 2008 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2008.312

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Shape control of fullerene microparticles by using ethylenediamine Reviewed

Matsuoka K.I., Matsumura S., Akiyama T., Yamada S.

Chemistry Letters 37 ( 9 ) 932 - 933 2008.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemistry Letters

[60,70]-Fullerene-ethylenediamine microparticles with sub-μn size were obtained by simply mixing fullerene and ethylenediamine in organic solvents under ambient condition. Amazingly, well-defined rhombic dodecahedral particles were obtained for C -ethylenediamine adducts only in the mixing ratio of C :ethylenediamine = 1:1000. Copyright © 2008 The Chemical Society of Japan. 70 70

DOI： 10.1246/cl.2008.932

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Enhanced photocurrent generation in self-assembled monolayers formed at plasmonic gold nanostructures Reviewed

Akiyama T., Nakada M., Sugawa K., Yamada S.

Macromolecular Symposia 270 ( 1 ) 171 - 176 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Macromolecular Symposia

The effect of localized surface plasmon resonance (SPR) appearing at the surfaces of gold nanoparticles (AuPs) was successfully applied for the enhancement of photocurrents from porphyrin (Po) immobilized on AuPs. The electrode consisting of AuPs with different sizes (∼15 or ∼35 nm) was prepared using the AuP film formed at the liquid/liquid interface, and then Po was self-assembled on the gold surface. The SPR effect for the AuP film was verified from the attenuated total reflection SPR and absorption measurements. Photocurrents from the modified electrodes were compared with the corresponding planar electrode. Appreciable enhancement of photocurrents was observed. Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

DOI： 10.1002/masy.200851020

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Step-by-step fabrication of porphyrin-fullerene supramolecular assemblies and their photoelectrochemical properties Reviewed

Matsuoka K.I., Akiyama T., Yamada S.

Journal of Physical Chemistry C 112 ( 17 ) 7015 - 7020 2008.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Physical Chemistry C

Porphyrin-fullerene C multilayered films have been successfully fabricated on an indium-tin-oxide (ITO) substrate by step-by-step, self-assembling, and surface sol-gel processes. First, cysteamine was self-assembled on the ITO surface, and then a C layer was formed via N-H addition reaction. The layered C further underwent another N-H addition with 1,2-diaminoethane to enable formation of the subsequent C layer, giving a double-layered C film. Meanwhile, the layered C was treated with 2-aminoethanol to implant hydroxy groups on the C layer, which was essential to promote the surface sol-gel reaction with titanium-(IV) butoxide for implanting the titanium oxide layer. Then tetracarboxyphenylporphyrin was superimposed on the titanium oxide layer by the subsequent surface sol-gel reaction. By repeating these surface sol-gel reactions, the porphyrin layer was further assembled on the outermost layer. Accordingly, the porphyrin and C multilayered films could be fabricated by the series of above-described step-by-step reactions. Absorption, fluorescence, quartz crystal microbalance, and photoelectrochemical investigations were carried out. Considerable photoinduced electron transfer between photoexcited porphyrin to C was verified, even in the presence of the titanium oxide linking layer. Appreciable photocurrent generation from the multilayered films was observed, and its mechanism is described. © 2008 American Chemical Society. 60 60 60 60 60 60 60 60 60

DOI： 10.1021/jp711180m

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Papers - AKIYAMA Tsuyoshi