| 高分子 Vol.63 No.11 |
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特集 ここまできた！熱電変換
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| 展望 COVER STORY: Highlight Reviews |
| 理論・計算シミュレーションを活用した熱電材料研究への展望 Toward Computational Simulation Aided Screening for High Performance Thermoelectric Material Search |
浅井 美博 Yoshihiro ASAI |
| ＜要旨＞ 精密な理論に則って発熱、伝熱、熱散逸、熱エネルギー変換等の熱問題を詳細に議論することが可能になっている。ナノエレクトロニクス分野での熱問題への応用が進んでいるが、熱電材料にも応用可能である。このアプローチを中心として、理論・計算シミュレーションを活用した熱電材料研究の現状と展望について概観する。 Keywords: Thermoelectric Figure of Merit / First Principle Non-Equilibrium Green Function (NEGF) Method |
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| 有機高分子およびハイブリッド熱電変換材料の開発 Recent Progress of Organic and Hybrid Thermoelectric Materials |
戸嶋 直樹 Naoki TOSHIMA |
| ＜要旨＞ 有機熱電変換材料は、熱を直接電気に変換できる機能をもつ。近年、導電率とゼーベック係数の改善により、導電性高分子の性能は急速に向上してきている。さらに無機ナノ材料とのハイブリッド形成も性能向上に有効であることがわかってきた。環境に優しく軽くてフレキシブルで大面積の素子を印刷技術で作製できるという特徴のゆえに、この技術は低品位廃熱や自然熱からのエネルギーの回収に有効と期待されている。 Keywords: Organic Thermoelectric Materials / Conducting Polymers / PEDOT / Hybrid Materials / CNT / Thermoelectric Figure-of-Merit / Electrical Conductivity / Thermal Management |
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| ナノ構造熱電材料の開発動向 Development of Nanostructured Thermoelectric Materials |
太田 裕道 Hiromichi OHTA |
| ＜要旨＞ 熱電材料の高性能化のキーはナノ構造制御である。1993年にMITのDresselhausらがナノ構造制御の有用性を理論予測して以来、ナノ構造制御による高ZT値（＞2）が報告されるようになった。本稿では、ナノ構造制御によるキャリア量子閉じ込め効果を利用した熱電能増強と最近の微細構造制御による低熱伝導率化に関する研究動向を紹介する。 Keywords: Nano-Structure Control / Quantum Confinment Effect / Superlattices / Two-Dimensional Electron Gas (2DEG) / Phonon-Glass Electron-Crystal / Lattice Thermal Conductivity |
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| トピックス COVER STORY: Topics and Products |
| カーボンナノチューブの分離精製と高効率熱電変換材料への展開 Separation of Single-wall Carbon Nanotubes Towards High Efficiency Thermoelectric Devices |
片浦 弘道 Hiromichi KATAURA |
| ＜要旨＞ Because 50% of used energy is wasted as heat in Japan, utilizing waste heat could greatly contribute preventing global warming and energy saving. Thin film, flexible, and high performance at low temperature thermoelectric devices are desirable for that purpose. Very recently, Maniwa et al. revealed that semiconducting SWCNT separated from pristine mixture has very large Seebeck coefficient at room temperature, while metallic SWCNT shows low value. This surprising difference can be explained by well- known Mott’s equation. We have demonstrated a thermocouple device constructed from junctions of metallic and semiconducting SWCNTs. Because SWCNT is robust, flexible, chemically inactive, and highly conductive, SWCNT can be a candidate material for high efficiency thin film thermoelectric devices. Low cost and large scale metal / semiconductor separation method of SWCNT was developed in NEDO project. Supply of low price semiconducting SWCNT could be possible in near future. Keywords: Thermoelectric Device / Carbon Nanotube / Separation / Seebeck Coefficient |
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| 高分子ナノ構造を鋳型として利用する高効率フレキシブルBi2Te3系熱電変換材料 Flexible Porous Bismuth Telluride Thin Films with Enhanced Figure of Merit Using Micro-Phase Separation of a Block Copolymer |
宮崎 康次 Koji MIYAZAKI |
| ＜要旨＞ We made porous thermoelectric thin films by using a block copolymer as the template. The nano-porous structure was made over a large area by using a phase separation of a block copolymer (PMMA-b-PMAPOSS). The Bismuth telluride was deposited on a porous polymer film. The thermal conductivities of the porous thermoelectric thin films were lower than that of bulk value due to long phonon mean free path, and the non-dimensional figure of merit was enhanced. A prototype thermoelectric module consisting of 20 pairs of p- and n-type strips was fabricated on the porous polyimide substrate. This module produced an output power of 0.1 mW and the output power was 1.5 times greater than that of a module based on flat Bismuth telluride thin films. Keywords: Thermoelectric / ZT Enhancement / Block Copolymer / Porous / Thermal Conductivity / Phonon |
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| エネルギーハーベストを目指したフレキシブル有機熱電変換材料 Flexible Organic Thermoelectric Materials for Energy Harvesting |
青合 利明 Toshiaki AOAI |
| ＜要旨＞ By using a photo acid generator (PAG), photo-induced doping to conductive polymers was investigated. The homogeneous film comprised of conductive polymers and PAGs, such as sulfonium salts, could be prepared without aggregation on coating and gave good conductivity after UV irradiation of the film. With the increase of PAG content and UV dose, the conductivity of the film showed higher values. The photo doping method was also effective for CNT / conductive polymer composites as another organic thermoelectric materials, which produced much higher conductivity and values of more than ZT=0.3. Utilizing the CNT composite materials, a flexible organic thermoelectric module was prepared through mask printing process and showed the possibility for an energy harvesting device. Keywords: Photo Doping / Photo Acid Generator / Organic Thermoelectric / Conductive Polymer / Carbon Nanotube Composite / Flexible Thermoelectric Module |
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| バイオナノ接合を利用したカーボンナノチューブ熱電複合材料における熱およびキャリア流の独立制御 Independent Control of Carrier and Heat Flow in Carbon Nanotube Thermoelectric Composites Using Bio-Nano Junctions |
中村 雅一 Masakazu NAKAMURA |
| ＜要旨＞ Carbon nanotubes (CNTs) are an attractive material for flexible thermoelectric devices because of their mechanical strength and high electrical conductivity. However, their thermoelectric performance is restricted by the large thermal conductivity. In this work, a novel method to improve performance by inserting bio-based molecules at CNT/CNT junctions is proposed. Thermal conductivity is dramatically suppressed, but electrical conductivity increases by the addition of cage-shaped proteins with semiconducting cores. The Seebeck coefficient can be increased by the selection of core material. By the improvements in all of the three important parameters above, the thermoelectric figure of merit (ZT) increases over 1000-fold. Keywords: Carbon Nanotube / Cage-Shaped Protein / Bio-Nano Junction / Thermoelectricity |
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| グローイングポリマー Polymer Science and I: A Personal Account |
| 人のため、社会のための研究を目指して Aspiring to Do Excellent Research for People and Society |
梶原 ゆり Yuri KAJIHARA |
| ＜要旨＞ In my college days, I learned not only how to promote my research but also aquired a wide range of knowledge in life. I finally found my enthusiasm to do excellent research for the benefit of people and society. Now as a company reseacher, I aspire that the resin I develop should bring new values to the world. |
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| 高分子科学最近の進歩 Front-Line Polymer Science |
| 高分子結晶化とコンピュータ・シミュレーション Molecular Simulations of Polymer Crystallization |
山本 隆 Takashi YAMAMOTO |
| ＜要旨＞ Computer modeling is acquiring ever increasing significance in the science and technology of polymers. In this article, we review recent advances in computer simulation of polymer crystallization. We here deal with several topics of great relevance, the basic elementary process of polymer crystallization, the characteristic crystallization behavior of polymers having specific molecular structures, the very fast crystallization during deformation and flow, and the crystallization in confined spaces and interfaces with other materials. We here emphasize the great potential of the computer modeling, and the challenges for the future. Keywords: Computer Modeling / Polymer Crystallization / Primary Nucleation / Crystal Growth / Helical Polymers / Comb-Like Polymers / Multi-Scale Modeling |
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