研究者詳細 - 林　靖彦

論文 - 林　靖彦

分割表示 262 件中 201 - 220 件目／全件表示 >>

Synthesis, morphology and random laser action of ZnO nanostructures 査読

L. Miao, S. Tanemura, Y. Ieda, M. Tanemura, Y. Hayashi, H. Y. Yang, S. P. Lau, B. K. Tay, Y. G. Cao

SURFACE SCIENCE 601 ( 13 ) 2660 - 2663 2007年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Three-dimensional (3-D) ZnO random-wall nanostructures and one-dimensional (I-D) ZnO nanorods were prepared on silicon substrates by a simple solid-vapour phase thermal sublimation technique. Optical pumped random lasing has been observed in the ZnO random-wall arrays with a threshold intensity of 0.38 MW/cm(2) in the emission wavelength from 380 to 395 nm. The optical gain was attributed to the closed-loop scattering and light amplification of the ZnO random-wall. The experimental result suggests that the morphology of nanostructure is the key factor to effect random lasing. (C) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.susc.2006.12.011

その他リンク： http://orcid.org/0000-0002-4113-5548

Encapsluation of Co and Pd multi-metal nanowires inside multiwalled carbon nanotubes by microwave plasma chemical vapor deposition 査読

Yasuhiko Hayashi, T. Fujita, T. Tokunaga, K. Kaneko, T. Butler, N. Rupesinghe, J. D. Carey, S. R. P. Silva, G. A. J. Amaratunga

DIAMOND AND RELATED MATERIALS 16 ( 4-7 ) 1200 - 1203 2007年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

We report the synthesis of multiwalled carbon nanotubes (MWCNTs) encapsulated with Co/Pd magnetic and nonmagnetic multi-metal nanowires using Co and Pd thin-layers deposited on Si substrate by microwave plasma enhanced chemical vapor deposition using a bias-enhanced growth method. Detailed structural and compositional investigations of these metal nanowires inside MWCNTs were carried out by scanning electron microscopy and transmission electron microscopy to elucidate the growth mechanisms. Energy dispersive X-ray spectroscopy revealed that MWCNTs were encapsulated with Co and Pd nanowires, separately, at the tube top and the bottom of Co nanowire, respectively. The face-centered-cubic (fcc) structure of Co nanowires was confirmed by a selected area diffraction pattern. We proposed a fruitful description for the encapsulating mechanisms of both Co and Pd multi-metal nanowires. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.diamond.2006.11.039

Encapsulation of segmented Pd-Co nanocomposites into vertically aligned carbon nanotubes by plasma-hydrogen-induced demixing 査読

Takeshi Fujita, Yasuhiko Hayashi, Tomoharu Tokunaga, T. Butler, N. L. Rupesinghe, K. B. K. Teo, G. A. J. Amaratunga

APPLIED PHYSICS LETTERS 90 ( 13 ) 2007年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

Vertically aligned carbon nanotubes (VA-CNTs) filled with Pd-Co nanocomposites on an Si substrate have been synthesized by microwave plasma-enhanced chemical vapor deposition. It was confirmed that adjacent Pd-Co nanocomposites in the VA-CNTs were compositionally separated. Most CNTs contained Co pillars on top; however, Pd pillars were rarely present. The strong magnetic induction from an individual Co pillar was revealed by electron holography. The simultaneous phenomenon of the demixing by plasma hydrogen irradiation and the preferential encapsulation into CNTs realized the unique Pd-Co nanocomposites. (c) 2007 American Institute of Physics.

DOI： 10.1063/1.2718268

その他リンク： http://orcid.org/0000-0002-4113-5548

Morphological and optical characterization of post-annealed ZnO films prepared by sol-gel method 査読

F. Y. Ran, L. Miao, S. Tanemura, M. Tanemura, Y. G. Cao, Y. Kuno, Y. Hayashi, Y. Mori

TRANSACTIONS OF THE MATERIALS RESEARCH SOCIETY OF JAPAN, VOL 32, NO 4 32 ( 4 ) 1247 - 1250 2007年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：MATERIALS RESEARCH SOCIETY JAPAN-MRS-J

Transparent zinc oxide (ZnO) films have been prepared by sol-gel method using spin coating method on quartz glass from 0.5M zinc acetate 2-methoxyethonal solution, and using monoethanolamine(MEA) as stabilizer. The as-prepared samples were heat-treated at 550 degrees C for 90min in air, oxygen and vacuum ambient, respectively. XRD patterns show that the prepared samples exhibit wurtzite structure, the sample annealed in O-2 has best crystalline quality and biggest degree of preferential orientation of (0O2) plane, and the sample annealed in vacuum nearly has,no preferential orientation. It can be found from AFM images that surface roughness of the three films are: Vacuum > air > O-2. The sample annealed in O-2 has rod-like and uniform particles, the sample annealed in air with ball-like particles and sample heat treated under vacuum ambient with ball-like uniform particles. PL analysis tells that vacuum atmosphere leads to more oxygen vacancy (VO) and zinc excess, however annealed in O-2 can decrease the oxygen vacancy (VO) and zinc excess obviously. The band gap of prepared ZnO films is about 3.3eV from PL spectra. Through analyze the UV-Vis result, it can be found that the surface morphology does influence the absorptance. Generally speaking, the annealed ambient influences the intrinsic defect and extrinsic defect, and then influence the properties of prepared ZnO films.

Microstructure analyses of metal-filled carbon nanotubes synthesized by microwave plasma-enhanced chemical vapor deposition 査読

Yasuhiko Hayashi, Tomoharu Tokunaga, Kenji Kaneko, Simon J. Henley, Vlad Stolojan, J. David Carey, S. R. P. Silva

IEEE TRANSACTIONS ON NANOTECHNOLOGY 5 ( 5 ) 485 - 490 2006年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Pd/Co-based metal-filled carbon nanotubes (MF-CNTs) were synthesized by a microwave plasma-enhanced chemical vapor deposition method using a bias-enhanced growth technique. Pd/Co-based MF-CNTs were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) electron energy loss spectroscopy (EELS), and Raman spectroscopy. MF-CNTs were well-aligned and uniform in size on a Si substrate. Both multiwall nanotube carbon nanotubes (CNTs) and herringbone (or stacked cups structure) structures were observed. High-resolution TEM revealed that MF-CNTs were composed of highly ordered graphite layers, and the elemental maps of EELS indicate that both Co and Pd metals are present inside the nanotubes. TEM results clearly showed that both Pd and Co metals were successfully encapsulated into the CNTs. We observed a low value for the Raman intensity ratio between D (1355 cm(-1)) and G (1590 cm(-1)) bands with no shift of the G-peak position and no broadening of the G-peak, indicative of high-quality Pd/Co-based MF-CNTs. Based on TEM characterization, we propose a description for the encapsulating mechanisms.

DOI： 10.1109/TNANO.2006.880456

Demixing of solid-soluted Co-Pd binary alloy induced by microwave plasma hydrogen irradiation technique 査読

Tomoharu Tokunaga, Yasuhiko Hayashi, Takeshi Fujita, S. R. P. Silva, G. A. J. Amaratunga

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45 ( 29-32 ) L860 - L863 2006年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：INST PURE APPLIED PHYSICS

Demixing in a solid-soluted Co-40 at. % Pd alloy has been induced by microwave plasma hydrogen irradiation on mixture of Pd-Co island grains on Si substrate. The microstructure observation and X-ray microanalysis by a transmission electron microscope before and after the microwave plasma hydrogen irradiation provide a clear evidence of demixing in metallic Co-Pd alloys, that may indicate a possibility of the decomposition into Pd hydride and Co under a hydrogen irradiation at high temperatures.

DOI： 10.1143/JJAP.45.L860

その他リンク： http://orcid.org/0000-0002-4113-5548

Low resistivity p-ZnO films fabricated by sol-gel spin coating 査読

Yongge Cao, Lei Miao, Sakae Tanemura, Masaki Tanemura, Yohei Kuno, Yasuhiko Hayashi

APPLIED PHYSICS LETTERS 88 ( 25 ) 2006年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

N-doped and In-N-codoped ZnO films were fabricated on quartz glass substrate by sol-gel spin coating. Their p-type conductivities were characterized by the Hall measurements, revealing low resistivities of the order of 10(-1) Omega cm. Thin-film junctions comprising an undoped ZnO layer and a N-doped ZnO layer displayed the typical rectifying characteristics, suggesting formation of p-n homojunctions at the interfaces. (c) 2006 American Institute of Physics.

DOI： 10.1063/1.2215618

その他リンク： http://orcid.org/0000-0002-4113-5548

Cobalt nanorods fully encapsulated in carbon nanotube and magnetization measurements by off-axis electron holography 査読

T Fujita, Y Hayashi, T Tokunaga, K Yamamoto

APPLIED PHYSICS LETTERS 88 ( 24 ) 2006年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

Fully encapsulated face-centered-cubic (fcc) Co nanorods in multiwalled carbon nanotubes were produced by microwave plasma enhanced chemical vapor deposition. Quantitative magnetization measurements of the Co nanorods were carried out by off-axis electron holography using a theoretical cylindrical model. The component of magnetic induction was then measured to be 1.2 +/- 0.1 T, which is lower than the expected saturation magnetization of fcc Co of 1.7 T. The reason for the reduced magnetic component was discussed.

DOI： 10.1063/1.2213202

その他リンク： http://orcid.org/0000-0002-4113-5548

Characterization of transport properties of multiwalled carbon nanotube networks by microwave plasma chemical vapor deposition 査読

Yasuhiko Hayashi, T. Tokunaga, K. Kaneko, Z. Horita

DIAMOND AND RELATED MATERIALS 15 ( 4-8 ) 1138 - 1142 2006年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

We report the synthesis of multiwalled carbon nanotubes (MWCNTs) and the characterization of ternperature-dependent electrical transport properties of MWCNT networks by using a two-point configuration without the lithographical technique. MWCNTs were grown by microwave plasma chemical vapor deposition with the bias enhanced growth technique. The Raman intensity ratio between the D- (similar to 1360 cm(-1)) and G- (similar to 1590 cm(-1)) peaks (I(D)/I(G)) as well as the full width at half maximum of the G-peak decreased from 1.03 to 0.03 and 18 to 13 cm(-1), respectively, with the increase in the oxidative purification time. This indicates that the crystallinity of graphite sheets is improved by the oxidative purification process and burn-off of the defects in MWCNT networks. The metal electrodes were attached on both the top and the bottom of the insulating thin films, and the as-grown and oxidative-purified MWCNT networks were connected between the electrodes for I-V measurements at various temperatures. At room temperature, the conductance for the MWNT networks at around zero bias was 0.65 G(0) (G(0): fundamental conductance unit), which was less than the value of 1 G(0) for metallic MWCNTs. Further, the conductance increased linearly with the bias voltage until it attained its peak. In the 190-390 K range, the temperature characteristic of the I-V shows that the electron transport of the as-grown MWCNT networks was activated by a lower activation energy than that in oxidative-purified MWCNT networks. (c) 2006 Elsevier B.V All rights reserved.

DOI： 10.1016/j.diamond.2006.01.006

その他リンク： http://orcid.org/0000-0002-4113-5548

Characterization of amorphous carbon nitride by bottom-gated thin-film structure 査読

Yasuhiko Hayashi, N. Kamada, T. Soga, T. Jimbo

DIAMOND AND RELATED MATERIALS 15 ( 4-8 ) 1015 - 1018 2006年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

We describe the characterization of nitrogen-incorporated amorphous carbon (a-C:N) films by using a double beam method. The carrier transport of a-C:N films deposited at various substrate temperatures was investigated using a bottom-gated thin-film transistor (TFT). At substrate temperatures below 300 degrees C, the optical band gap (E-opt) and the Raman intensity ratio between the D (similar to 1360cm(-1)) and G (similar to 1590cm(-1)) peaks (I-D/I-G) of an a-C:N film deposited at room temperature were observed to vary only marginally from 1.9eV and 0.88, respectively. The electrical conductivity of the a-C:N film increased by more than four orders of magnitude with an increase in the substrate temperature from 150 to 300 degrees C due to an improvement in the activation of the nitrogen-incorporated a-C film caused by the thermal annealing effect. Based on the E-opt and I-D/I-G values, we concluded that this behavior is not responsible for the change in the hybridization of carbon atoms. The a-C:N based TFT exhibited an ambipolar transport with the strong p-type operation. The field effect hole mobility (mu(h)) attained a value as high as 1.7 x 10(-4) cm(2)/Vs. In this study, one of the important results is that mu(h) increased with the substrate temperature due to the increase in film conductivity. We found that the highest success yield of transistor operation of 38% was obtained from the a-C:N TFTs deposited at a substrate temperature of 290 degrees C. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.diamond.2006.01.009

その他リンク： http://orcid.org/0000-0002-4113-5548

Optical properties of indium-doped ZnO films 査読

YG Cao, L Miao, S Tanemura, M Tanemura, Y Kuno, Y Hayashi, Y Mori

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45 ( 3A ) 1623 - 1628 2006年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：INST PURE APPLIED PHYSICS

Indium-doped ZnO (IZO) films with low In content (< 6at.%) were fabricated by rf helicon inagnetron sputtering. The uniformity of the composites was confirmed by elemental analysis. The formation of an In-Zn-O solid Solution was verified using X-ray diffraction (XRD) patterns. A wide, high-transmittance re ion (400-2000 nm) and > 80% transmittance in the window of fiber optics telecommunication (1.30-1.55 mu m) were observed. The incorporation of indium enhances the optical transmission in the designated visible and infrared wavelengths. The optical band gap shows a slight blue-shift with increasing In doping which call be explained by the Burstein-Moss effect. The Urbach tail parameter E-0 increases with increasing indium content, which coincides with the increase in the full width half maximum (FWHM) of (0002) planes in XRD patterns. A decline in crystal quality with In incorporation in IZO films is also confirmed from photoluminescence (PL) spectra.

DOI： 10.1143/JJAP.45.1623

その他リンク： http://orcid.org/0000-0002-4113-5548

Microstructure analyses of metal-filled carbon nanotubes synthesized by microwave plasma-enhanced chemical vapour deposition 査読

Y. Hayashi, T. Tokunaga, K. Kaneko, S. J. Henley, V. Stolojan, J. D. Carey, S. R. P. Silva

2006 IEEE CONFERENCE ON EMERGING TECHNOLOGIES - NANOELECTRONICS 5 ( 5 ) 93 - + 2006年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Pd/Co-based metal-filled carbon nanotubes (MF-CNTs) were synthesized by a microwave plasma-enhanced chemical vapour deposition method using a bias-enhanced growth technique. Pd/Co-based MF-CNTs were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) electron energy loss spectroscopy (EELS), and Raman spectroscopy. MF-CNTs were well-aligned and uniform in size on a Si substrate. Both multiwall nanotube carbon nanotubes (CNTs) and herringbone (or stacked cups structure) structures were observed. High-resolution TEM revealed that MF-CNTs were composed of highly ordered graphite layers, and the elemental maps of. EELS indicate that both Co and Pd metals are present inside the nanotubes. TEM results clearly showed that both Pd and Co metals were successfully encapsulated into the CNTs.. We observed a low value for the Raman intensity ratio between D (1355 cm(-1)) and G (1590 cm(-1)) bands with no shift of the G-peak position and no broadening of the G-peak, indicative of high quality Pd/Co-based MF-CNTs. Based on TEM characterization, we propose a description for the encapsulating mechanisms.

DOI： 10.1109/TNANO.2006.880456

その他リンク： http://orcid.org/0000-0002-4113-5548

Investigation of PCBM concentration on photovoltaic characteristics of polymer solar cells with blends of P3HT and PCBM 査読

Yasuhiko Hayashi, K. Hamada, K. Takagi, A. Takasu, S. Takagi, T. Soga

CONFERENCE RECORD OF THE 2006 IEEE 4TH WORLD CONFERENCE ON PHOTOVOLTAIC ENERGY CONVERSION, VOLS 1 AND 2 1 271 - 274 2006年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Polymer photovoltaic cells (PVCs) consisting of a blend of p-type poly(3-hexylthiophene) (P3HT) and n-type [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) were fabricated and Investigated the role of the PCBM concentration. The photocurrent and the power conversion efficiency gradually increased with increase in PCBM concentration up to 50% and decreased with further increase In PCBM concentration. Both the root mean square and average roughnesses measured by atomic force microscopy decrease as the PCBM concentration increases from 0 to approximately 70%. The surface morphology of P3HT/PCBM blended and improved donor-acceptor proximity, leading to electron conductivity, contribute to the increase in power conversion efficiency.

DOI： 10.1109/WCPEC.2006.279443

その他リンク： http://orcid.org/0000-0002-4113-5548

Microstructure analyses of metal-filled carbon nanotubes synthesized by microwave plasma-enhanced chemical vapour deposition 査読

Y. Hayashi, T. Tokunaga, K. Kaneko, S. J. Henley, V. Stolojan, J. D. Carey, S. R. P. Silva

2006 IEEE CONFERENCE ON EMERGING TECHNOLOGIES - NANOELECTRONICS 2006 93 - + 2006年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Pd/Co-based metal-filled carbon nanotubes (MF-CNTs) were synthesized by a microwave plasma-enhanced chemical vapour deposition method using a bias-enhanced growth technique. Pd/Co-based MF-CNTs were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) electron energy loss spectroscopy (EELS), and Raman spectroscopy. MF-CNTs were well-aligned and uniform in size on a Si substrate. Both multiwall nanotube carbon nanotubes (CNTs) and herringbone (or stacked cups structure) structures were observed. High-resolution TEM revealed that MF-CNTs were composed of highly ordered graphite layers, and the elemental maps of. EELS indicate that both Co and Pd metals are present inside the nanotubes. TEM results clearly showed that both Pd and Co metals were successfully encapsulated into the CNTs.. We observed a low value for the Raman intensity ratio between D (1355 cm(-1)) and G (1590 cm(-1)) bands with no shift of the G-peak position and no broadening of the G-peak, indicative of high quality Pd/Co-based MF-CNTs. Based on TEM characterization, we propose a description for the encapsulating mechanisms.

DOI： 10.1109/NANOEL.2006.1609696

その他リンク： http://orcid.org/0000-0002-4113-5548

A study on visually disabled person support system utilizing led traffic light with visible light communication technology 査読

Suzuki K, Fujita M, Fukuzono K, Mizuno H, Hayashi Y

13th World Congress on Intelligent Transport Systems and Services 2006年

Effects of indium incorporation on the optical properties of ZnO films 査読

Cao, Y., Miao, L., Tanemura, S., Hayashi, Y., Tanemura, M.

Advanced Materials Research 11-12 159 - 162 2006年

Structural and optical characterization of ZnO single crystalline nanobamboos 査読

L Miao, S Tanemura, Y Hayashi, M Tanemura, RP Wang, S Toh, K Kaneko

INTERNATIONAL JOURNAL OF MODERN PHYSICS B 19 ( 15-17 ) 2804 - 2810 2005年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WORLD SCIENTIFIC PUBL CO PTE LTD

ZnO nanobamboos and nanowires with diameters of 10-30 nm and lengths of 2-4 mu m have been prepared by laser ablation in vacuum with precisely controlled pressure, growth and post-annealing temperature. XRD results show the annealed sample is hexagonal ZnO. Low-magnified TEM observation reveals the annealed sample includes ZnO nanobamboos and nanowires. High resolution TEM image and electron diffraction pattern confirm that the structure of ZnO nanobamboo is regular stacking of Zn and 0 layers with high crystal quality. The growth direction is determined as along [001] direction (c axis). TEM observations confirm that the formation of bamboo-shape ZnO is due to the stacking fault and cleavage. The bundle of those stacking faults seems to be the origin of the black contrast at the nodes. The uniformity of chemical composition for the nanobamboos is identified by EDS profiles. A strong-narrow UV band centred at 390 nm and a weak-broad green band centred at 515 nm are observed at room temperature in the PL spectrum recorded from the annealed ZnO nanobamboos and nanowires.

DOI： 10.1142/S0217979205031730

その他リンク： http://orcid.org/0000-0002-4113-5548

Formation of wedge-shaped carbon film by chemical vapor deposition method and observation using transmission electron microscopy 査読

K Kaneko, R Nagayama, K Inoke, WJ Moon, Z Horita, Y Hayashi, T Tokunaga

SCRIPTA MATERIALIA 52 ( 12 ) 1205 - 1209 2005年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Unusual morphologies of carbon nanofibers (CNFs) fabricated by the microwave plasma-enhanced chemical vapor deposition method were confirmed by transmission electron microscopy. In particular, the presence and distribution of wedge-shaped carbon films, consisting of amorphous carbon and CNFs, were observed by three-dimensional electron tomography (3D-ET), and their growth mechanisms were modeled. High-resolution transmission electron microscopy (HRTEM) revealed the presence of amorphous carbon on carbon nanofibers. Wedge-shaped carbon films are most likely caused by the bridging of individual CNFs by amorphous carbon from plasmarized carbon. The combination of 3D-ET and HRTEM clearly provides a successful strategy for determining 3D morphologies with characteristic sizes on the nanometer scale. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.scriptamat.2005.03.007

その他リンク： http://orcid.org/0000-0002-4113-5548

Effect of rf power on the photovoltaic properties of boron-doped amorphous carbon/n-type silicon junction fabricated by plasma enhanced chemical vapor deposition 査読

T Soga, T Kokubu, Y Hayashi, T Jimbo

THIN SOLID FILMS 482 ( 1-2 ) 86 - 89 2005年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

The optical and electrical properties of boron doped amorphous carbon thin films using methane and trimethylboron by plasma enhanced chemical vapor deposition are studied with varying the rf power. The optical bandgap is decreased from 2.4 to 1.4 eV with increasing the rf power due to the increase of sp(2) carbon. The boron doped amorphous carbon deposited at 300 W shows large photoconductivity (the ratio of conductivity under illumination to under dark) with high spin density. The open circuit voltage of boron doped amorphous carbon/n-Si structure photovoltaic cell is increased with the increase of rf power and then saturates over 100 W. On the other hand, the short circuit current is increased gradually with increasing the rf power up to 300 W. (c) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2004.11.123

その他リンク： http://orcid.org/0000-0002-4113-5548

Influence of structure and C-60 composition on properties of blends and bilayers of organic donor-acceptor polymer/C-60 photovoltaic devices 査読

Y Hayashi, Yamada, I, S Takagi, A Takasu, T Soga, T Jimbo

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44 ( 3 ) 1296 - 1300 2005年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPAN SOC APPLIED PHYSICS

We have fabricated both blended and bilayered organic photovoltaic cells (OPVCs) using C-60 and poly [2-methoxy-5-(2'-ethyihexoxy)-1,4-phenylenevinylene] (MEH-PPV). Improvements in photovoltaic performance are seen in blended OPVCs when the C-60 concentration is increased. It is believed that the optimized surface morphology of MEH-PPV/C-60 Composite and improved donor-acceptor proximity, leading to electron conductivity, contribute to the increase in power conversion efficiency E-ff. Two broad peaks were observed in the spectral response of the blended OPVCs, with maximum peaks at similar to 490 nm (= I-BL1) and similar to 350 nm (= I-BL2). The intensity ratio of I-BL1 to I-BL2 (I-BL1/I-BL2) decreases with an increase in the C-60 concentration. Also, I-BL1 is blue-shifted by 25-30 nm with an increase in the C-60 concentration. The significant improvement in the performance was observed in the bilayered OPVCs on the thermally induced interdiffusion Of C-60 into the MEH-PPV network, leading to the existence of C-60 molecules within the exciton diffusion radius of the MEH-PPV, network. The spectral response of bilayered OPVCs reveals two peaks at 535 nm and 345 nm. The former peak is red-shifted by 45 nm compared to that in blended OPVCs. We also investigate the effect of top electrode materials on the photovoltaic performances. To the best of our knowledge, we have obtained the best performances of blended and bilayered OPVCs fabricated with the Al and Mg electrodes, respectively. In both OPVC structures, the nanoscale composition control of the two materials, the choice of metal electrode, and the device processing techniques all play an important role in determining or enhancing the solar cell performance.

DOI： 10.1143/JJAP.44.1296

その他リンク： http://orcid.org/0000-0002-4113-5548

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