小柴 康子 | ![]() |
コシバ ヤスコ | |
大学院工学研究科 応用化学専攻 | |
助手 | |
応用化学関係 |
Thermoelectric power generation from waste heat is an important component of future sustainable development. Ion-conducting materials are promising candidates because of their high Seebeck coefficients. This study demonstrates that ionic hydrogels based on imidazolium chloride salts exhibit outstanding Seebeck coefficients of up to 10 mV K-1. Along with their relatively high ionic conductivities (1.6 mS cm(-1)) and extremely low thermal conductivities (similar to 0.2 W m(-1) K-1), these hydrogels have good potential for use in heat recovery systems. The voltage behavior in response to temperature difference (stable or transient) differs significantly depending on the metal electrode material. We evaluated the electrode-dependent temperature sensitivity of the double layer capacitance of these hydrogels, which revealed that the thermally induced polarization of ions at the interface is one of the main contributors to the thermovoltage. Our results demonstrate the potential capability for ion and metal interactions to be used as an effective baseline for exploring ionic thermoelectric materials and devices. The developed thermoelectric supercapacitor exhibits reversible charging-discharging behavior under repeated disconnecting-connecting of an external load with a constant temperature difference, which offers a novel strategy for heat-to-electricity energy conversion from steady-temperature heat sources.
AMER CHEMICAL SOC, 2020年09月, ACS APPLIED MATERIALS & INTERFACES, 12 (39), 43674 - 43683, 英語研究論文(学術雑誌)
pi-Conjugated dendrimers are emerging platforms for molecular-based photonics and electronics. Herein, we demonstrate thiophene dendrimers as new thermoelectric (TE) materials with large Seebeck coefficients through chemical charge-carrier doping, conducting film preparation, and TE transport evaluations (electrical conductivity and Seebeck coefficient). Complementary characterization with absorption, photoelectron spectroscopy, and molecular calculations reveals that the highly degenerate frontier molecular orbital energy levels derived from the highly branched and symmetric molecular structures of the dendrimers play an important role in the anomalously large Seebeck coefficients based on Mott's equation. With the recent rapid progress in the technologies for synthesizing pi-conjugated dendrimers and molecular designing flexibilities, our results propose a novel strategy for exploring new TE materials.
ROYAL SOC CHEMISTRY, 2020年05月, MOLECULAR SYSTEMS DESIGN & ENGINEERING, 5 (4), 809 - 814, 英語研究論文(学術雑誌)
We report a new near infrared (NIR) absorbing dye, phenyl-fused dibenzo-BODIPY with benzo[1,3,2]oxazaborinine rings (PhBODIPY), for organic photodiode (PDs). PhBODIPY can be deposited on the substrates without thermal decomposition and its deposited film is amorphous state with high thermal stability. The deposited film showed broadband absorption in the wavelength range of 600-1000 nm. The NIR-OPD with PhBODIPY film demonstrated a detectivity (D*) of 7.41 x 10(11) Jones under NIR light irradiation at a wavelength of 820 nm. The D* improved to 1.70 x 10(12) Jones by co-deposition of 1:1 (w/w) PhBODIPY:fullerene (C-60). The photocurrent was maximized under light irradiation at a wavelength of 694 nm, corresponding to the absorption wavelength of H aggregated state of PhBODIPY molecules. The formation of Haggregated state is important to further improve OPD characteristics. (C) 2020 The Japan Society of Applied Physics
IOP Publishing, 2020年02月05日, Japanese Journal of Applied Physics, 59 (SG), SGGG04 - SGGG04, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Poly(3,4-ethylenedioxythiophene) (PEDOT) was fabricated via vapor-phase polymerization (VPP) of the monomer 3,4-ethylenedioxythiophene (EDOT) with FeCl3?6H(2)O melt as the oxidant at the EDOT vapor?FeCl3?6H(2)O melt interface. Highly doped VPP-PEDOT films were formed on the oxidant melt surfaces. The morphological changes and decrease in the doping level at the VPP-PEDOT film surface were attributed to slower oxidant transport up to the surface during VPP. The doping level of VPP-PEDOT was higher when the oxidant melt was used compared to when the oxidant thin film was employed, and the maximum doping level was twice of that obtained in our previous work.
TAYLOR & FRANCIS LTD, 2019年10月, Molecular Crystal and Liquid Crystals, 688 (1), 53 - 59, 英語[査読有り]
研究論文(学術雑誌)
© 2018, The Society of Polymer Science, Japan. In this study, semiconductive elastomers composed of homopolythiophene with disiloxane moieties were developed. The crosslinked molecular structure in the polythiophene elastomers was introduced by dicumyl peroxide, one of the typical peroxide crosslinking reagents. The elastomers were produced through a hot-pressing process above the melting point of the polythiophene. Stress–strain curves that included tensile tests and cycle loading–unloading tests defined the crosslinked polythiophenes as elastomers. Their electrical conductivities were evaluated by two-point measurements under nondeformation and uniaxial deformation states. The results indicated that the concentration of crosslinking reagents greatly influenced the mechanical and electrical properties of crosslinking polymers. With the addition of the crosslinking reagent in concentrations from 2.5 phr to 10.0 phr, elongation at break decreased largely from 95% to 51%, while excellent elastic recoveries were observed. In the electrical resistivity measurements, all the crosslinking polymers possessed high stability of electrical properties against elongation.
2019年02月01日, Polymer Journal, 51 (2), 257 - 263, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Thin films of poly(3,4-ethylenedioxythiophene) (PEDOT) were fabricated via the vapor-phase polymerization (VPP) of the monomer 3,4-ethylenedioxythiophene (EDOT) with FeCl3 center dot 6H(2)O as the oxidant. The doping level and electrical properties of the VPP-PEDOT films were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrical conductivity measurements. The VPP of EDOT was observed by in situ ultraviolet-visible (UV-Vis) absorption spectroscopy. The results showed that highly doped PEDOT films were formed in the initial stages of VPP, and the doping level increased as the reaction proceeded. The doping level eventually decreased because of the limited amount of the oxidant. Therefore, it was concluded that the doping level of VPP-PEDOT thin films could be changed depending on the initial amount and supply of the oxidant. The thermoelectric properties of the as-synthesized VPP-PEDOT films were also studied, with the aim of applying them as an energy harvester and/or a temperature sensor.
MYU, SCIENTIFIC PUBLISHING DIVISION, 2018年12月, Sensors and Materials, 30 (12), 2873 - 2879, 英語[査読有り]
研究論文(学術雑誌)
研究論文(研究会,シンポジウム資料等)
[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Urea is expected to be used as a reducing agent in the photocatalytic formation of hydrogen from water because it is a non-petroleum material and abundant in domestic wastewater. In this study, a TiO2 catalyst co-doped with tantalum(V) and a trivalent metal cation, serving as promoters, was applied for the photocatalytic decomposition of water for hydrogen production using urea as the reducing agent. Co-doping of TiO2 with tantalum(V) and a trivalent metal cation resulted in a considerable redshift of the absorption edge of TiO2 via the formation of impurity levels. In particular, the incorporation of tantalum(V) and chromium(III) into TiO2 resulted in significant performance enhancement for the photocatalytic decomposition of water for hydrogen production. The products obtained from the photodecomposition of water with urea were also identified, and urea was transformed into N2 and CO2 during the reaction. Moreover, the reaction was performed using thin-film photocatalysts based on organic semiconductors, such as picene, representing a class of novel, unconventional photocatalytic materials. Picene thin-films exhibited activity similar to that exhibited by traditional inorganic semiconductors. Effective utilisation of urea has potential application in a green and sustainable production of hydrogen from wastewater via photocatalysis using various semiconductors.
Elsevier B.V., 2018年06月01日, Catalysis Today, 307, 231 - 236, 英語[査読有り]
研究論文(学術雑誌)
The low volatility of ionic liquids (ILs) is one of their most interesting physico-chemical properties; however, the general understanding of their evaporation dynamics under vacuum is still lagging. Here, we studied the thermodynamics of IL evaporation by employing thermogravimetry (TG) measurements under vacuum. The thermodynamic parameters of ILs, such as the evaporation onset temperatures, enthalpies, entropies, saturation vapor pressures, and boiling points were quantified by analyzing the TG data. The obtained evaporation enthalpies (110-140 kJ mol(-1)) were higher than those of typical molecular liquids, and the entropies (>88 J mol(-1) K-1) suggested that they are exceptions of the Trouton's rule. The obtained Clausius-Clapeyron equations demonstrated that the saturation vapor pressures of ILs only depend on temperature. Further, we derived the empirical equation for estimating the upper limit temperature of the liquid phase of IL under given external pressures. Using the evaporation behaviors of referential normal alkanes and charge-transfer complex and the evaporation entropies of the ILs, the vaporized IL structure was thermodynamically modelled. The ILs were found to evaporate as ion pairs, instead of as individual ions or higher-ordered cluster structures. By comparing a series of ILs with various cations and a fixed anion, it was found that the IL evaporation dynamics under vacuum is strongly and systematically affected by their chemical structures, charge balances between the cations and the anions, molecular weights, and the higher-ordered structures including polar and non-polar regions. Our concept, measurement method, and equation can be extended to other ILs and low-volatile liquids under vacuum, and help with the design of ILs with higher thermal stabilities.
ROYAL SOC CHEMISTRY, 2018年06月, Physical Chemistry Chemical Physics, 20 (33), 21262 - 21268, 英語[査読有り]
研究論文(学術雑誌)
Carbon nanotubes (CNTs) dispersed in water by sonication with surfactants are used as printing inks. However, surfactants are usually electrical insulators that remain on the prepared CNT films, reducing their conductivity. While evaporation by annealing is an effective removal process, it is usually performed at high temperatures (180 degrees C) in air, making it inapplicable for printing on common plastic substrates. This work demonstrates a vacuum annealing process for evaporating surfactants. Poly(oxyethylene) 4 lauryl ether (Brij L4)-a nonionic surfactant-was utilized. Its evaporation behaviors (thermodynamics and kinetics) were analyzed by thermogravimetric (TG) analysis and infrared (IR) spectroscopy. The TG measurements confirmed that the evaporation onset temperature under vacuum (51.0 degrees C) was lower than that in air (148.7 degrees C). The IR results revealed that similar to 100% Brij L4 was removed by annealing under vacuum at 130 degrees C. The desorption energy of the surfactant from CNTs was calculated from the activation energy results to be about 10 kJ mol(-1); this value is about a half to one order of magnitude smaller than those reported for other surfactants. This energy would allow adequate adsorption interactions for the surfactant to stably disperse the nanotubes, but is sufficiently small to allow easy removal of the surfactant by thermal treatment. The electrical resistance of the vacuum-annealed CNT thin film dramatically decreased compared with that of the film annealed in air. Therefore, this process can be used for fabricating flexible printed electronics with CNTs.
IOP PUBLISHING LTD, 2018年06月, Flexible and Printed Electronics, 3 (2), 025006, 英語[査読有り]
研究論文(学術雑誌)
Piezoelectric gels were prepared from low-volatile ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) gels, and their structural, ferroelectric, and piezoelectric properties were investigated. Poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE)/IL gels were formed using thermally reversible physical gels. The structural characterization indicated that the P(VDF-TrFE) molecules in the gels predominantly formed a ferroelectric phase (Form I) of P(VDF-TrFE). Polarization switching peaks were clearly observed using a three-layer stacked device structure. The coercive field of the P(VDF-TrFE)/IL gels substantially decreased to 4-9 MV/m, and their remnant polarizations were maintained at 63-71 mC/m2, which is similar to that for typical solid-state P(VDF-TrFE). Finally, the P(VDF-TrFE)/IL gel films exhibited a piezoelectric response, and the highest piezoelectric coefficient was ∼300 pm/V at an applied voltage frequency of 4kHz.
Japan Society of Applied Physics, 2018年04月01日, Japanese Journal of Applied Physics, 57 (4), 04FL06 - 1-6, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The surface modification of ferroelectric films is expected to improve the properties of fatigue, which is important for application in memory devices. In this study, we fabricated thin insulators at an electrode-ferroelectric interface by the phase separation of a ferroelectric polymer and an insulator. The surface and bulk characterization indicated that the insulators consisting of a hyperbranched polymer spontaneously phase-separated from the organic ferroelectric polymer by thermal annealing. It was revealed that the separated layers were composed of three layers and had a lower surface energy than the ferroelectric films. The annealing time evolution of the surface contact angle and dielectric spectra indicated the phase separation dynamics and structural behavior. The fatigue properties of the surface-modified ferroelectric films improved, but the remanent polarization and coercive electric field value resulted in a trade-off.
Japan Society of Applied Physics, 2018年03月01日, Japanese Journal of Applied Physics, 57 (3), 03EG02 - 1-6, 英語[査読有り]
研究論文(国際会議プロシーディングス)
This paper describes an evaluation of ionic liquids (ILs) as potential electrolytes for single-layered light-emitting devices with good emission performance. As optoelectronic devices continue to grow in abundance, high-performance light-emitting devices with a single emission layer are becoming increasingly important for low-cost production. We show that a simple technique of osmosing IL into the polymer layer can result in high luminous efficiency and good response times of single-layered light-emitting polymers, even without the additional stacking of charge carrier injection and transport layers. The IL contributions to the light-emission of the polymer are discussed from the perspectives of energy diagrams and of the electric double layers on the electrodes. Our findings enable a faster, cheaper, and lower-in-waste production of light-emitting devices.
Japan Society of Applied Physics, 2018年03月01日, Japanese Journal of Applied Physics, 57 (3), 03EH02 - 1-4, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Here, we studied the charge-carrier modulation of single-walled carbon nanotubes (SWCNTs) via poly(vinyl acetate) (PVAc) doping and dedoping under ultraviolet (UV) light irradiation with the aim of pairing several p- and n-type SWCNTs as thermoelectric (TE) elements. The Seebeck coefficient of the SWCNTs was first made negative by doping with PVAc and then made positive again through UV-induced PVAc dedoping. A possible TE module configuration and the process for its fabrication are proposed, wherein prints and photopatterns can be obtained without the use of additional electrodes. Our findings enable the fabrication of fine TE modules using simple materials and techniques.
Elsevier B.V., 2018年01月01日, Chemical Physics Letters, 691, 219 - 223, 英語[査読有り]
研究論文(学術雑誌)
Single-walled carbon nanotubes (SWCNTs) are important candidates for flexible and non-toxic thermoelectric (TE) energy-harvesting devices because they have large Seebeck coefficients, good flexibility, and inkjet printability onto plastic substrates. Here we describe the successful n-type conversion of intrinsic p-type SWCNTs by polymer-dopant charge transfer. The negative Seebeck coefficients of the polymer-doped SWCNTs were strongly related to the highest occupied molecular orbital levels of the polymer, demonstrating that the polymers were electron donors for the nanotubes and that the doping level could be controlled by modifying the functional groups. The n-type SWCNTs obtained using oxygen-abundant polymers, such as poly(vinyl alcohol) and poly(vinyl acetate), exhibited the largest negative Seebeck coefficients and high stability under ambient conditions lasting for at least 3 weeks. Printed and folded p- and n-type SWCNTs on flexible substrates showed efficient TE voltage improvements. Our findings enable the easy, low-cost preparation of air-stable n-type SWCNTs, permitting the exploitation of SWCNTs as flexible and eco-friendly TE materials.
Royal Society of Chemistry, 2017年12月01日, Molecular Systems Design and Engineering, 2 (5), 616 - 623, 英語[査読有り]
研究論文(学術雑誌)
研究論文(国際会議プロシーディングス)
We investigated piezoelectric vibration energy harvesters with poly(vinylidene fluoride/trifluoroethylene) films and the improved power generation from using multistacked and stretched ferroelectric films on the cantilevers. The energy harvesters generated electric power with a resonant frequency of approximately 25 Hz, which corresponded to the ambient vibration. The power density of four-layered harvesters was estimated to be 2.5μW/m3, which was larger than the power density of previous harvesters. The output power of stretched-film harvesters was 3.6 times the output obtained from unstretched films. In addition, because organic ferroelectric films are flexible, the resonant frequency of each harvester was practically constant even when using the techniques of multistacking and stretching.
Japan Society of Applied Physics, 2017年04月01日, Japanese Journal of Applied Physics, 56 (4), 04CL04 - 1-4, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The structural, ferroelectric, and piezoelectric properties of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] gels fabricated using poly(pyridinium-1,4-diyliminocarbonyl-1,4-phenylenemethylene thiocyanate) (PICPM-SCN) as a gelator are investigated in this study. The P(VDF-TrFE)/PICPM-SCN composites formed thermally reversible physical gels and their analysis by Fourier transform infrared spectroscopy revealed that the P(VDF-TrFE) molecules in these gels exhibit predominantly the ferroelectric phase I (Form beta). Furthermore, the polarization switching peaks of the P(VDF-TrFE)/PICPM-SCN gel films were clearly observed. The coercive electric field for these gel films was estimated to be 2 MV/m, which is dramatically lower than the values typically observed for P(VDF-TrFE) solid films (50 MV/m). Finally, the P(VDF-TrFE)/PICPM-SCN gel films exhibited a piezoelectric response, and the highest piezoelectric coefficient was determined to be similar to 53 pm/V at an applied voltage frequency of 4 kHz. (C) 2017 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2017年04月, Japanese Journal of Applied Physics, 56 (4), 04CL03 - 1-5, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
We investigated the piezoelectric properties of a vibration energy harvester using large-area, flexible cantilevers composed of polyurea thin films. The piezoelectric constant d(31) of the polyurea films was measured based on the relationship between the displacement and applied voltage of large-aspect-ratio cantilevers. Centimeter-scale unimorph cantilevers were fabricated, and their energy harvester performance was evaluated by vibrating them. The power generation of the cantilevers with controlled forms was 2.2mV at 50.5Hz (i.e., vibration generation could be efficiently realized at environmental vibrations under 100 Hz).
TAYLOR & FRANCIS LTD, 2017年, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 653 (1), 188 - 193, 英語[査読有り]
研究論文(学術雑誌)
CuPc nanorod growth was investigated on ITO substrates with and without 1H,1H,2H,2H-perfluoro-noctylphosphonic acid (FOPA) SAM modification, using vapor phase deposition, through the control of the temperature and surface energy of ITO substrates. At a substrate temperature of 200 degrees C, copper phthalocyanine (CuPc) thin films that composed nanorods were prepared on both substrates. On FOPA-ITO, it was suggested that CuPc molecules were stacked with an edge-on orientation because of the dominant intermolecular - interaction through the decrease of surface energy of ITO with FOPA modification. Organic photovoltaic cells containing CuPc nanorods as a p-type semiconductor were fabricated and photovoltaic characteristics were observed.
TAYLOR & FRANCIS LTD, 2017年, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 653 (1), 157 - 163, 英語[査読有り]
研究論文(学術雑誌)
Crystal growth of Alga was achieved in an ionic liquid by vacuum vapor deposition. Alq(3) crystals of several tens of microns in size showed beautiful hexagonal morphologies, different from previous reports. The successful crystal growth can be explained by the enhanced migration of Alga molecules and moderate supersaturation within the ionic liquid. The Alq(3) crystal showed unique optical properties, such as a waveguide and blue-shift of the photoluminescence spectrum.
CHEMICAL SOC JAPAN, 2016年10月, CHEMISTRY LETTERS, 45 (10), 1156 - 1158, 英語[査読有り]
研究論文(学術雑誌)
Interesting photocatalytic properties of a picene thin film on quartz (PTF/Q) have been demonstrated for photocatalytic hydrogen formation from water using several sacrificial agents. Hydrogen is produced in the presence of PTF/Q catalysts under light irradiation, indicating that PTF/Q works as a photocatalyst. The catalyst retains its activity under light irradiation and addition of sacrificial agents enhanced the rate of photocatalytic hydrogen formation from water, similar to the condition when a traditional inorganic photocatalyst is used. Moreover, PTF/Qcatalysts comprising picene films of different thickness have been fabricated, and PTF/Q with the thinnest film (50 nm) exhibits the highest activity for hydrogen formation. X-ray diffraction patterns show that the picene crystals are vertically aligned on the surface of the quartz sheet, and that PTF/Q with the thinnest film has a nonuniform film phase. The difference of picene thin-film surface in morphology probably influences the photocatalytic activity. The absorption edge and optical gap energies of the prepared PTF/Q catalyst are determined and the optical gap of the picene film is calculated to be 3.2 eV. (C) 2016 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2016年09月, APPLIED CATALYSIS B-ENVIRONMENTAL, 192, 88 - 92, 英語[査読有り]
研究論文(学術雑誌)
The tuning of the Seebeck coefficient of a single-walled carbon nanotube (SWCNT) film was achieved by using the dipole field of a ferroelectric polymer. The Seebeck coefficient was positive under an up-poling dipole field, but negative under a down-poling dipole field, whereas the control remained positive. This tunable behavior can be explained by selective carrier injection and accumulation, which was confirmed by the temperature dependence of electrical conductivity. Connecting p- and n-type SWCNT films tuned by dipole fields to create a pi module resulted in a significant improvement in output voltage owing to the temperature difference between the two. (C) 2016 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2016年08月, APPLIED PHYSICS EXPRESS, 9 (8), 081301 - 1-4, 英語[査読有り]
研究論文(学術雑誌)
研究論文(研究会,シンポジウム資料等)
We have investigated the thermoelectric power of single-wall carbon nanotubes (SWCNTs) with an ionic liquid (IL). The SWCNT/IL films showed simultaneous increase in electrical conductivity and the Seebeck coefficient compared with the pristine SWCNT. No thermoelectric power was observed for the IL. The X-ray diffraction pattern and impedance diagram showed a unique behavior with the concentration of IL, which implies that the interaction between the SWCNTs and IL enhances the thermoelectric power of the SWCNTs. As a result of the simultaneous increase in these parameters, the power factor exhibited a 10-fold increase. (C) 2016 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2016年03月, JAPANESE JOURNAL OF APPLIED PHYSICS, 55 (3), 03DC01 - 1-5, 英語[査読有り]
研究論文(学術雑誌)
The thermal behavior of 1,2,4,5-tetracyanobenzene (TCNB), the synthesis of metal-2,3,9,10,16,17,23,24-octacyanophthalocyanine-metal [ MPc(CN)(8)-M] (M = Cu, Fe, Ni) complexes by the tetramerization of TCNB, and the growth of MPc(CN)(8)-M nanorods were investigated. By chemical vapor deposition (CVD) in vacuum, MPc(CN)(8) molecules were synthesized and MPc(CN)(8)-M nanorods were formed on all substrates. Among them, CuPc(CN)(8) molecules were synthesized in high yield, and CuPc(CN)(8)-Cu nanorods were deposited uniformly and in high density, with diameters and lengths of 70-110 and 200-700 nm, respectively. The differences in the growth of MPc(CN)(8)-M nanorods were mainly attributed to the stability of the MPc(CN)8-M complex, the oxidation of ultrathin metal films, and the diffusion of metal atoms. Additionally, the tetramerization of TCNB by CVD at atmospheric pressure was performed on ultrathin Cu films, and the synthesis of CuPc(CN)(8) molecules was observed by in situ UV-vis spectroscopy. CVD under atmospheric pressure is also useful for the synthesis of CuPc(CN)(8) molecules. (C) 2016 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2016年03月, JAPANESE JOURNAL OF APPLIED PHYSICS, 55 (3), 03DD07 - 1-5, 英語[査読有り]
研究論文(学術雑誌)
The structures of blended films composed of a light-emitting polymer and an ionic liquid were investigated, and the relationship between the emission properties of organic light-emitting diodes (OLEDs) and the structure of the blended films was discussed. We have demonstrated emission in positive and negative biases of the blended films, which contributed to the effects of the electric double layer. Moreover, we have visualized the distribution of the ionic liquid, not only in-plane but also out of-plane, by employing electroluminescence in a sandwich device. Ionic liquids form a micrometer-order phase-separation structure in the blended film and are found in higher concentration on the top of the film. Finally, we have summarized the guidelines for ideal film structure of single-layer OLEDs.
CHEMICAL SOC JAPAN, 2016年03月, CHEMISTRY LETTERS, 45 (3), 259 - 261, 英語[査読有り]
研究論文(学術雑誌)
Thin-film fabrication of polyurea is hindered by poor solubility in most organic solvents. We fabricated spin-coated thin films of polyurea and investigated the structural and electrical properties of the films. The as-spun films had rough surfaces and relatively high crystallinity with 4.5 nm grains, while melt-quenched films were smooth and lower in crystallinity with 2.7 nm grains. Residual solvent remained in the films at temperatures above the boiling point of the solvent. The quenched polyurea films exhibited large current peaks originating from activated impurity charges from the residual solvent in the current density-electric field curves. The pyroelectric coefficient of the spin-coated polyurea films was estimated to be 4.13 mu C/m(2)K. The polyurea films maintained pyroelectricity even after the application of an electric field, thereby exhibiting potential applicability in pyroelectric devices with annealing to remove the impurity charges. (C) 2015 Elsevier Ltd. All rights reserved.
ELSEVIER SCI LTD, 2015年11月, POLYMER, 79, 128 - 134, 英語[査読有り]
研究論文(学術雑誌)
The ferroelectric properties of perpendicularly oriented, highly crystalline vinylidene fluoride (VDF) oligomer thin films were investigated by using a planar device configuration consisting of comblike Cr-Au electrodes with a 1 mu m gap. In-plane polarization switching was induced by the rotation of the VDF oligomer. As the measurement temperature was increased from 295 to 380 K, the coercive field (E-c) decreased drastically from 124 to 7.7MV/m. Furthermore, the thermal stability of our device significantly improved compared with that of conventional sandwiched devices utilizing VDF oligomer films with a parallel orientation. (C) 2015 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2015年11月, APPLIED PHYSICS EXPRESS, 8 (11), 11601 - 1-3, 英語[査読有り]
研究論文(学術雑誌)
We have investigated the temperature dependence of the piezoelectric coefficients and infrared sensor performance of spin-coated thin films of polyundecylurea (PUA11). The piezoelectric coefficients of the PUA11 films remained constant at temperatures above 180 degrees C and these films demonstrated thermal resistance superior to those of poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)] films. The infrared sensor performance of the PUA11 films was measured after annealing at 125 degrees C for 500 h and was found to have retained 84% of its preannealing level. The thermal stability of the PUA11 films was higher than that of the P(VDF/TrFE) films; moreover, PUA11 is also expected to have superior electrothermal stability. (C) 2015 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2015年10月, APPLIED PHYSICS EXPRESS, 8 (10), 101501 - 1-3, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
We proposed a novel method for micro-patterning organic semiconductor layers by using a laser irradiation system. The method was demonstrated with a precursor that changes solubility after thermal conversion. For micro-scale patterning, brief irradiation was crucial to prevent heat diffusion in the substrate. We found that preheating on a hot-plate is important for shortening the laser irradiation time necessary for the thermal conversion. The patterning resolution also depended on the kind of substrates as well as the laser exposure time. High-resolution line patterns with a width of 12 μm were successfully achieved on ITO substrates. Organic light-emitting diodes utilizing a patterned emitting layer, with line widths of 20 μm and spacing of 85 μm, were demonstrated.
Institute of Image Information and Television Engineers, 2015年, ITE Transactions on Media Technology and Applications, 3 (2), 143 - 148, 英語[査読有り]
研究論文(学術雑誌)
The crystal growth and unique morphological changes of organic semiconductor rubrene, fabricated by ionic liquid (IL)-assisted vacuum vapor deposition, were investigated. The texture and structure of rubrene films strongly depended on the thickness of IL films on substrates, namely, three-dimensional dendrites in 3D-ILs, two-dimensional microfibrils in 2D-ILs, and two-dimensional spherulites in 0D-ILs. The growth of two-dimensional spherulites would be promoted by the supersaturation of ILs, minutely controlling the rate and total amount of rubrene deposition. The growth mechanisms of rubrene fabricated by IL-assisted vacuum vapor deposition were different from that of the conventional one in terms of the nucleation and growth modes. (C) 2014 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2014年05月, JAPANESE JOURNAL OF APPLIED PHYSICS, 53 (5), 05FT03 - 1-4, 英語[査読有り]
研究論文(学術雑誌)
Organic photovoltaic (OPV) cells were fabricated using copper-2,3,9,10,16,17,23,24-octafluorophthalocyanine (F8CuPc) as an electron acceptor. Normal and inverted OPV cells using F8CuPc were showed rectification in dark and photovoltaic characteristics under illumination. The inverted-type cell had good durability. The power conversion efficiency (eta) of the inverted-type cell was 0.11%, approximately 6.5 times higher than that of the normal-type cell. The cell using F8CuPc was more stable than that using fullerene in air. These results indicate the possibility of using F8CuPc as an electron acceptor for air-stable OPV cells. (C) 2014 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2014年01月, Japanese Journal of Applied Physics, 53 (1), pp. 01AB04 - 1-4, 英語[査読有り]
研究論文(学術雑誌)
The ferroelectric properties of ferroelectric liquid crystals (FLCs) during thermal phase transition in the surface-stabilized ferroelectric liquid crystal (SSFLC) cells were examined. The coercive electric field (E-c) and remanent polarization (P-r) changed with increasing temperature. These temperature-dependent variations of E-c and P-r were in agreement with the differential scanning calorimetry results. Moreover, the fatigue characteristic of the SSFLC cells was examined. No polarized fatigue was observed after 1 x 10(6) cycles of polarization switching, because FLCs may have the self-repair property for structural and interfacial defects. (C) 2014 The Japan Society of Applied Physics
IOP PUBLISHING LTD, 2014年01月, JAPANESE JOURNAL OF APPLIED PHYSICS, 53 (1), 01AE07 - 1-4, 英語[査読有り]
研究論文(学術雑誌)
Uniaxially aligned single-crystals of ferroelectric vinylidene fluoride (VDF) oligomer were obtained on a highly-oriented ultra-thin film of vinylidene fluoride-trifluoroethylene copolymer P(VDF/TrFE). Trapezoidal shaped plate-like VDF oligomer crystals with 20 nm thickness were selectively grown perpendicularly on P(VDF/TrFE) lamella crystals as a structural template. Fourier transform infrared reflection absorption spectroscopy (FTIR-RAS) and synchrotron two-dimensional grazing incidence X-ray diffraction (2D-GIXD) revealed that the molecular chain axis (c-axis) of P(VDF/TrFE) oriented to the friction transfer direction with the a-axis perpendicular to the film surface, and the friction-transferred P(VDF/TrFE) film induced the uniaxially aligned nucleation of the VDF oligomer with an epitaxial relationship (010)[001](VDF-oligomer)//(100)[001](P(VDF/TrFE)) in initial crystal growth of VDF oligomer. (C) 2013 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2013年08月, MATERIALS LETTERS, 105, 227 - 231, 英語[査読有り]
研究論文(学術雑誌)
Dipotassium-2,3,9,10,16,17,23,24-octacyanophthalocyanine-potassium (K2Pc(CN)(8)-K) complex nanograss was fabricated on a single KCl crystal. The process was controlled to achieve monodisperse nanograss with individual rod diameters of 60 nm and lengths of 250 nm. The gaps between the rods were fully covered with K2Pc(CN)(8)-K complex grains. The film continuity at the interface between the substrate and the nanograss layer allowed measurement of the field-effect-transistor characteristics of the material. The K2Pc(CN)(8)-K complex film exhibited n-type conduction characteristics, and the energy of the highest occupied molecular orbital was determined to be 5.8 eV. Organic photovoltaic cells containing K2Pc(CN)(8)-K as an n-type semiconductor were also fabricated, and the power-conversion efficiency of a cell containing vertical-aligned-nanograss was approximately four times larger than that of a nanograss dispersed bulk-heterojunction-type cell. (C) 2013 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2013年03月, THIN SOLID FILMS, 531, 513 - 518, 英語[査読有り]
研究論文(学術雑誌)
Submicron-thick free-standing films of ferroelectric poly(vinylidene fluoride/trifluoroethylene) copolymer, P(VDF/TrFE), were fabricated and characterized for application in lead-free pyroelectric infrared sensors. The pyroelectric current and its responsivity were improved by the freestanding structure of the films owing to the reduced thermal capacity and suppression of thermal diffusion in the sensor element. The pyroelectric current for the 500-nm-thick free-standing film was about 20 times higher than that for a conventional "on-substrate'' P(VDF/TrFE) film element, and the thermal time constant for the 500-nm-thick free-standing film was shortened by 1/6 of that for a conventional "on-substrate'' P(VDF/TrFE) film element. (C) 2013 The Japan Society of Applied Physics
JAPAN SOC APPLIED PHYSICS, 2013年02月, APPLIED PHYSICS EXPRESS, 6 (2), 021601/1 - 021601/3, 英語[査読有り]
研究論文(学術雑誌)
Three types of bi-functionalized copolymers (P1FAz, P2FAz, and P3FAz) with different numbers of fluorene units and an azobenzene unit were synthesized and characterized using UVvis and polarized absorption spectroanalysis. The trans-cis photoisomerization was conformed under 400 nm light irradiation for all copolymers in chloroform. However, in the film state, only the trans-cis photoisomerization occurred by mono-fluorene attached copolymer poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-4,4'-azobenzene)] (P1FAz). Photo-induced alignment was achieved using the P1FAz film after irradiation with linear polarized 400 nm light and subsequent annealing at 60 degrees C. Surface orientation of a spin-coating film of poly(9,9-didodecylfluorene) (F12) was achieved using the photo-induced alignment layer of the P1FAz film after annealing at 90 degrees C. The photo-induced alignment layer of P1FAz has potential application to the surface orientation technique for appropriate polymers, which will be useful for the fabrication of optoelectronics devices. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
WILEY-BLACKWELL, 2012年12月, JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 50 (24), 5107 - 5114, 英語[査読有り]
研究論文(学術雑誌)
研究論文(研究会,シンポジウム資料等)
研究論文(研究会,シンポジウム資料等)
研究論文(研究会,シンポジウム資料等)
A uniaxially oriented film of ferroelectric vinylidene fluoride (VDF) oligomer was fabricated by vacuum deposition on a friction-transferred vinylidene fluoride-trifluoroethylene copolymer; i.e., P(VDF/TrFE), film as a structural template. Fourier transform infrared spectroscopy and scanning electron microscopy measurements revealed that the ultra thin P(VDF/TrFE) film induced the formation of the ferroelectric form I crystal phase and the uniaxial orientation of what to the VDF oligomer by epitaxial growth. The VDF oligomer/P(VDF/TrFE) films exhibit ferroelectric hysteresis loops with a coercive field and a remanent polarization of 150MV/m and 77mC/m(2), respectively; however, VDF oligomer films without a structural template showed no ferroelectric properties. (C) 2012 The Japan Society of Applied Physics
JAPAN SOC APPLIED PHYSICS, 2012年04月, JAPANESE JOURNAL OF APPLIED PHYSICS, 51 (4), 04DK05/1 - 04DK05/4, 英語[査読有り]
研究論文(学術雑誌)
Thin films of fluorescent molecules were prepared by friction-transfer and investigated by UV-vis absorption and PL measurements and TEM observation. Molecules with a long skeleton were aligned nearly horizontally and parallel to the friction direction in the film. Such in-plane orientation is advantageous in fabricating OLEDs with respect to light-outcoupling efficiency.
CHEMICAL SOC JAPAN, 2011年11月, CHEMISTRY LETTERS, 40 (11), 1288 - 1289, 英語[査読有り]
研究論文(学術雑誌)
In order to prepare the TiO2 liquid dispersions for the electrodes of dye-sensitized solar cells with industrial mass production level at a reasonable cost, the present study investigates the preparation of TiO2 liquid dispersions by a general industrial dispersion technique using readily available P25. To determine the TiO2 dispersion offering the best light-electricity energy conversion efficiency, the suitability of various types of solvents and resins for use in TiO2 dispersion are tested. In general, organic solvent based TiO2 dispersions are found to allow the formation of more uniform thin films in comparison with water-based dispersions. A preparation using ethyl cellulose as the resin and the terpineol as the solvent is found to exhibit the best conversion efficiency. We have also found that using two kinds of resins of different molecular weights gave rise to better efficiency. Among 26 metal compounds tested in this study, the best metal dopant was Ag. XRD and XPS measurements confirm that the Ag exists as metal Ag and silver oxide.
SPRINGER, 2011年03月, JOURNAL OF MATERIALS SCIENCE, 46 (5), 1341 - 1350, 英語[査読有り]
研究論文(学術雑誌)
In order to prepare the TiO2 liquid dispersions for the electrodes of dye-sensitized solar cells with industrial mass production level at a reasonable cost, the present study investigates the preparation of TiO2 liquid dispersions by a general industrial dispersion technique using readily available P25. To determine the TiO2 dispersion offering the best light-electricity energy conversion efficiency, the suitability of various types of solvents and resins for use in TiO2 dispersion are tested. In general, organic solvent based TiO2 dispersions are found to allow the formation of more uniform thin films in comparison with water-based dispersions. A preparation using ethyl cellulose as the resin and the terpineol as the solvent is found to exhibit the best conversion efficiency. We have also found that using two kinds of resins of different molecular weights gave rise to better efficiency. Among 26 metal compounds tested in this study, the best metal dopant was Ag. XRD and XPS measurements confirm that the Ag exists as metal Ag and silver oxide.
SPRINGER, 2011年03月, JOURNAL OF MATERIALS SCIENCE, 46 (5), 1341 - 1350, 英語[査読有り]
研究論文(学術雑誌)
The detailed structure of crystalline beta-phase poly(9,9-dioctylfluorene) (PFO) films was studied by polarized optical measurements, transmission electron microscopy, and grazing-incidence X-ray diffraction. Crystalline beta-phase PFO thin films were fabricated by a friction transfer technique and subsequent vapor treatment. Compared to the alpha-phase, the lattice parameters of the beta-phase crystals shrank along the a-axis (film thickness direction) and elongated along the b-axis (side-chain direction), but the period along the c-axis (main-chain direction) remained nearly equal. These changes in molecular packing were consistent with a planar conformational change from the alpha-phase to the beta-phase of PFO. (C) 2010 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2011年01月, Thin Solid Films, 519 (7), 2247 - 2250, 英語[査読有り]
研究論文(学術雑誌)
The current-voltage characteristics of benzoporphine-fullerene solar cells were measured subsequent to the deposition of Al as a cathode material. Even in vacuum, a shift in the open circuit voltage was observed at 20 min after Al deposition. Moreover, the displacement of inert gases (N(2) or Ar) in the evaporation chamber enhanced the photovoltaic parameters. The power conversion efficiency was increased by 24% over the initial characteristics (from 1.04% to 1.29%), which indicates that the structure of the organic-metal interface changed rapidly after Al deposition, even if the process was performed in an air-free glovebox. (C) 2010 American Institute of Physics. [doi:10.1063/1.3516469]
AMER INST PHYSICS, 2010年11月, APPLIED PHYSICS LETTERS, 97 (19), 英語[査読有り]
研究論文(学術雑誌)
One-dimensionally oriented poly(9,9-dioctylfluorene-co-bithiophene) (F8T2) thin films with the thickness of approximately 50 nm were deposited by friction-transfer technique. Films were investigated using polarized optical spectroscopy. The dichroic ratio of absorption was estimated to be approximately eight. By means of transmission electron microscope (TEM), we revealed that the main-chains of F8T2 were aligned along the friction direction. Atomic force microscope (AFM) images of as-prepared films showed a roughened surface, whereas the film after subsequent thermal treatment showed remarkably smooth surface. Field-effect transistors utilizing the friction-transferred F8T2 films exhibited a field-effect mobility of 1.88 x 10(-4) cm(2) V-1 s(-1) along the friction direction, which is about six times higher than that perpendicular to the friction direction. (C) 2010 The Japan Society of Applied Physics
JAPAN SOC APPLIED PHYSICS, 2010年, Jpn. J. Appl. Phys., 49 (1), 英語[査読有り]
研究論文(学術雑誌)
The conformationat change and the alignment behavior of poly-4BCMU were investigated in compression, de-compression and re-compression process using LB method. In compression process, the conformation of poly-4BCMU changed from random-coil conformation to rigid-rod one. With the increase of surface pressure, poly-4BCMU with rigid-rod conformation gathered into bundles and they aligned perpendicular to the compressing direction. Once stopping the compression and releasing the surface pressure, the bundle textures released packing. In this process (de-compression process), the conformational change never occurred. Discrete slender fibrils gathered again in re-compression process, resulting in the formation of close-packed bundles with high molecular ordering. (C) 2009 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2009年11月, THIN SOLID FILMS, 518 (2), 819 - 823, 英語[査読有り]
研究論文(学術雑誌)
Photo-induced molecular alignment behavior of spin-coated poly(4,4'-azo benzene pyromellitamic acid) (PAA(azo)) film was investigated by Fourier transform infrared spectroscopy measurement, atomic force microscope and transmission electron microscope observation. As-spun PAA(azo) flm was found to be smooth and uniform with an amorphous structure. Upon irradiation of linearly polarized ultraviolet light, the molecular ordering and crystallization were induced, and the film surface was roughened slightly. The PAA (azo) film converted to poly(4,4'-azobenzene pyromellitimide) (PI(azo)) film with higher ordering and crystallinity by subsequent thermal treatment. The PI(azo) film was useful as an active layer to introduce the molecular alignment of copper phthalocyanine (CuPc). (C) 2009 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2009年11月, THIN SOLID FILMS, 518 (2), 805 - 809, 英語[査読有り]
研究論文(学術雑誌)
A cationic spiropyran iodide derivative (SPI) was synthesized as a photoresponsive compound, and SPI/montmorillonite clay hybrid films were prepared using ion- and guest-exchange intercalation methods. When the ion-exchange method was applied to clay with a low cation-exchange capacity (CEC) intercalation, of SPI into clay interlayers did not occur. Using the clay with a high CEC SPI was intercalated into clay interlayer and the interlayer distances were elongated. Upon UV and visible light irradiation, SPI in hybrid film photoisomerized reversibly and the interlayer distance also changed reversibly. On the other hand, intercalation by the guest-exchange method using cethyltrimethylammoniumbromide (CTAB) as a preexchanging reagent was independent on the CEC. After the addition of SPI, the CTAB in the clay interlayers was exchanged for SPI, but a partial CTAB remained in the interlayer. SPI in the hybrid films prepared by the guest-exchange method photoisomerized reversibly without any change in interplanar distance due to the coexisted CTAB. (C) 2009 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2009年11月, THIN SOLID FILMS, 518 (2), 651 - 655, 英語[査読有り]
研究論文(学術雑誌)
Leuco dye indicates the reversible coloring reaction with acidic compounds (called developer) having long-chain moiety. In order to clarify the structural change between colored state and decolored one of this system, X-ray diffraction (XRD) measurements and transmission electron microscope (TEM) observations were performed. It was found that mixture of leuco dye and developer took different layered structures between colored and decolored state. This structural change shows intercalation and deintercalation of leuco dye occur in the reversible coloring process. The mechanism of coloring/decoloring reaction of leuco dye with long-chain molecule is proposed. (c) 2007 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2008年03月, THIN SOLID FILMS, 516 (9), 2591 - 2594, 英語[査読有り]
研究論文(学術雑誌)
Photo-induced molecular alignment behavior of azo dye derivative (sodium 4,4'-bis (4-hydroxy-3-carboxy-phenylazo) benzidine-2,2'disulphonate: SDI) was investigated using SDI film prepared by spin-coating method. As-prepared SDI film was composed of an amorphous layer with smooth surface. Upon linearly polarized UV light irradiation, the film surface was roughened slightly and X-ray diffraction measurement and transmittance electron microscope observation indicated that SDI molecules crystallized with orientation. Molecular plane of SDI aligned parallel to the substrate surface along the normal to the polarization direction of irradiated UV light through the trans-cis and cis-trans isomerizations of the azobenzene chromophore. (c) 2007 Elsevier B.V. All tights reserved.
ELSEVIER SCIENCE SA, 2008年03月, THIN SOLID FILMS, 516 (9), 2686 - 2690, 英語[査読有り]
研究論文(学術雑誌)
Alignment structure and optical properties of Langmuir- Blodgett ( LB) films of urethane- substituted polydiacetylene ( poly-4BCMU) was investigated. During compression, the coil to rod transition in molecular conformation of poly- 4BCMU was induced and the polymer main chains were aligned perpendicular to the compressing direction. The dichroic ratio of absorption intensity of poly- 4BCMU monolayer film was about 6. LC molecules were sandwiched with two glass plates covered with the poly- 4BCMU monolayer films. LC molecules aligned spontaneously along the main chain direction of poly- 4BCMU in the parallel cell. On the other hand, they formed a twisted structure of 90 degrees in the crossed cell. The monolayer film of poly- 4BCMU had a high potential as rubbing- free alignment layer of LC molecules.
TAYLOR & FRANCIS LTD, 2007年03月, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 464, 701 - 708, 英語[査読有り]
研究論文(学術雑誌)
Liquid- crystalline polymer ( LCP) films were treated with N-2 plasma in order to improve adhesion with metal film. By N-2 plasma treatment, hydrophilic groups such as NH, COOH and OH were introduced into LCP film and the surface of the film was roughened slightly. After N-2 plasma treatment, a copper film was deposited on the LCP by electroless plating method. The circuit pattern of copper film with 0.5mm ( line) and 0.3mm ( space) intervals was fabricated on the LCP film.
TAYLOR & FRANCIS LTD, 2007年03月, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 464, 769 - 776, 英語[査読有り]
研究論文(学術雑誌)
In order to fabricate metal-free J-aggregate, merocyanine(MD)/spiropyran(SP) mixed LB film was transferred on a glass plate from a pure aqueous solution. Upon UV-light illumination, SP molecules isomerized from SP-form to photomerocyanine (PMC)-form and PMC-form molecules formed J-aggregate with self-assembly. Subsequent vapor-treatment of dimethylamine (DMA) aqueous solution after UV-light illumination induced J-aggregate formation of MD molecules. Metal-free J-aggregate of MD dye was formed by the stepwise treatment of UV illumination and the DMA vapor treatment. The formation mechanism of J-aggregate was discussed.
TAYLOR & FRANCIS LTD, 2007年, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 472, 513 - 520, 英語[査読有り]
研究論文(学術雑誌)
J-aggregate formation in the films of spiropyran derivatives ( SP1822 and SP18) prepared with Langumuir-Blodegett ( LB) and vapor-deposition methods was investigated. In the films of SP1822, J-aggregate formation occurred with UV light illumination and thermal treatment. In the case of SP18 film, on the other hand, only photoisomerization occurred. When the PMC-form of SP18 was transferred onto a glass plate, J-like aggregate formation occurred after UV light illumination. By UV light illumination during evaporation process, SP1822 formed J-aggregate. Finally, SP1822 J-aggregate film oriented one-dimensionally was fabricated by using a PTFE layer as a substrate.
TAYLOR & FRANCIS LTD, 2006年, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 445, 17 - 26, 英語[査読有り]
研究論文(学術雑誌)
Structural and optical property changes of p-sexiphenyl (6P) films induced by rubbing were investigated. 6P molecules vapor-deposited on a fused silica glass adsorbed obliquely but had no in-plane orientation. After rubbing, the film surface became smooth and the electron microscopic analysis revealed that the longitudinal direction of the 6P molecules is parallel to the substrate surface and oriented uniaxially along the rubbing direction. The absorption spectrum changed corresponding to the orientation change of the 6P molecules. The 6P molecules grew homoepitaxially on the rubbed film, and the film exhibited a high anisotropic optical property (dichroic ratio: 9.6) when deposition was performed at a low substrate temperature (RT) and a high deposition rate (5nm/min). © 2005 The Japan Society of Applied Physics.
2005年06月, Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, 44 (6 A), 4088 - 4091, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
研究論文(学術雑誌)
[査読有り]
[査読有り]
[査読有り]
[査読有り]
有機強誘電体フッ化ビニリデン・三フッ化エチレンランダム共重合体P(VDF/TrFE)に熱処理に伴って界面へ移動する性質をもつ有機ナノ粒子を混合し、絶縁層/強誘電体/絶縁層の3層構造の自発的な作製を試みた。AFM観察では有機ナノ粒子混合による膜形態への影響はみられなかったが、接触角測定において明確な表面改質効果が観察された。さらに、インピーダンス測定により誘電分散特性の解析を行った結果、界面に移動した有機ナノ粒子によって絶縁層/強誘電体絶縁の自発的な3層構造が作製されていることが示唆された。
一般社団法人電子情報通信学会, 2014年10月10日, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 114 (241), 27 - 31, 日本語真空熱重量示差熱分析同時測定(真空TG-DTA測定)によって、イオン液体[Emim][Tf2N]の熱物性測定を行った。大気圧下において[Emim][Tf2N]を加熱したところ分解挙動を示したのに対して、真空TG-DTA測定によって真空中で加熱すると[Emim][Tf2N]は蒸発挙動を示した。高真空下における蒸気圧を定量化したところ、5.0×10^<-6>Paという非常に小さな値が得られた。また本研究では、[Emim][Tf2N]はイオン対として蒸発しているという蒸発モデルの提案を行った。
一般社団法人電子情報通信学会, 2013年10月11日, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113 (243), 27 - 31, 日本語イオン液体[P13][TFSI]とフッ化ビニリデン・三フッ化エチレンランダム共重合体(P(VDF/TrFE))との界面を形成し、その電気特性を評価した。Al電極素子との比較から、観測初期においてイオン液体は電極として機能し、P(VDF/TrFE)のJEスイッチングピークは明確に観測されたが、分極反転を複数回繰り返す疲労特性においてはP(VDF/TrFE)膜厚による特性変化を示した。イオン液体/有機強誘電体界面での分極反転挙動を考察するため、各素子及びイオン液体のインピーダンス周波数特性評価を行った結果、低周波数域において差異が観察され、イオン液体/強誘電体の相互作用が示唆された。
一般社団法人電子情報通信学会, 2013年10月11日, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113 (243), 33 - 37, 日本語ITO基板上にフッ素末端基を有するホスホン酸系の自己組織化単分子膜(P-SAM)を成膜することで、その上に積層した銅フタロシアニン(CuPc)蒸着膜の配向・膜構造の制御を試みた。一般的に熱に強いとされるP-SAMを用いると、有機膜の蒸着時の基板温度の制御の幅が広がる。本実験では、P-SAMは真空下で523Kまで安定して存在することが確認された。298K・473Kの基板温度条件において真空蒸着法によりCuPc薄膜を作製し、配向・構造の評価を行った。P-SAMで修飾した基板上に、498Kの基板温度条件下においてCuPcを蒸着すると長さ数100nm〜1μmのピラーの成長が観察され、面外への成長が促進されることがわかった。また、P-SAMで修飾した基板上におけるCuPc薄膜中の分子配向は、基板面に平行な成分が増加していた。
一般社団法人電子情報通信学会, 2013年10月11日, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113 (243), 77 - 81, 日本語その他
有機半導体や高分子を有機EL,有機薄膜太陽電池あるいは有機FETに応用しようとする試みが活発である.有機薄膜素子の機能化には,目的に応じた分子配向制御が重要である.本報では,ポリテトラフルオロエチレン(PTFE)摩擦転写膜をテンプレートとして用いた有機分子の結晶成長とFET応用について報告する.
日本結晶成長学会, 2009年, 日本結晶成長学会誌, 35 (4), 227 - 233, 日本語炭酸カルシウム(CaCO<sub>3</sub>)のリン酸化反応により球状水酸アパタイト(HAp)を合成し,さらにシランカップリング剤,ソルビン酸および液状カルボキシル化ポリブタジエン(LB)により表面処理した.HAp および表面処理 HAp を構造の異なる 3 種のスチレン系熱可塑性エラストマー(TPS)に充てんし,複合体の力学特性に及ぼす影響を CaCO<sub>3</sub> およびシリカ(SiO<sub>2</sub>)充てん複合体と比較して検討した.HAp を充てんしたスチレン-イソプレン-スチレンブロックコポリマー(SIS)複合体の低伸長域の応力は,SiO<sub>2</sub> と CaCO<sub>3</sub> 充てん複合体に比べて高く,引張永久ひずみ(<i>T</i><sub>S</sub>)は小さくなった.表面処理 HAp の充てんにより,複合体の 300%伸長時のモジュラス(<i>M</i><sub>300</sub>)と破断強度(<i>T</i><sub>B</sub>)はさらに向上し,<i>T</i><sub>S</sub> は低下した.今回用いた修飾剤を比較すると,LB による表面処理効果が最も高かった.また,LB を含む溶液中で合成した HAp(IS-HAp)は,LB と HAp の複合粒子から形成されていた.IS-HAp は,不飽和の TPS に対して良好な補強効果を示し,充てんした複合体の耐熱性も向上した.<br>
公益社団法人 高分子学会, 2009年, 高分子論文集, 66 (9), 356 - 363, 日本語記事・総説・解説・論説等(学術雑誌)
[査読有り]
記事・総説・解説・論説等(学術雑誌)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
ポスター発表
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
競争的資金
競争的資金
競争的資金
競争的資金
競争的資金
競争的資金
競争的資金
競争的資金
競争的資金