九州大学 研究者情報
研究者情報 (研究者の方へ)入力に際してお困りですか?
基本情報 研究活動 教育活動 社会活動
大瀧 倫卓(おおたき みちたか) データ更新日:2023.11.27

教授 /  総合理工学研究院 物質科学部門 物性化学


主な研究テーマ
未利用熱エネルギー回収のための酸化物熱電材料の開発
キーワード:熱電変換材料,酸化物半導体,エネルギー変換材料,導電性セラミックス、熱伝導率、酸化亜鉛、ペロブスカイト型酸化物、層状コバルト酸化物、ナノボイド、ナノコンポジット
1991.07.
中高温廃熱回収用酸化物熱電モジュールの開発
キーワード:酸化亜鉛、層状コバルト酸化物、微細構造制御、高速高密度実装、電極接合技術、長期安定性評価、
2002.11.
低次元量子閉じ込め構造を持つ無機ナノ物質の自己組織合成と物性
キーワード:低次元ナノ物質、分子集合体、自己組織化、ナノ超格子、光触媒、磁性、無機有機複合体
1996.04.
特異量子物性を示す超集積構造の構築とナノ構造物性
キーワード:超集積量子構造、空間規則性、ナノスペース、層間相互後作用
1998.04.
従事しているプロジェクト研究
溶射法を利用した 熱電変換モジュールの研究開発
2017.04~2018.03, 代表者:増住 大地, (株)フジコー, 新エネルギー・産業技術総合開発機構
従来、バルク体で作製されてきた熱電変換素子について、表面コーティング技術の一種であり、低コスト化が実現可能な溶射法を用いた素子およびモジュールの高性能化を図り、熱源への設置および実用化を目指す。.
OTE-POWER – Oxide thermoelectrics for effective power generation from waste heat
2011.01~2014.12, 代表者:Nini Pryds, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, Danish Council for Independent Research, Technology and Production(デンマーク)
廃熱エネルギー発電を目的とした酸化物熱電モジュールの開発.
知的クラスター創成事業「超高効率化を実現するナノ構造熱電発電モジュールの開発」
2009.04~2012.03, 代表者:横野 照尚, 九州工業大学, 財団法人福岡県産業・科学技術振興財団
超高効率化を実現するナノ構造熱電発電モジュールの開発.
多元ドープによるバルクナノコンポジット構造ZnO系酸化物熱電材料の開発
2008.07~2009.03, 代表者:大瀧 倫卓, 九州大学, 科学技術振興機構
地域イノベーション創出総合支援事業 重点地域研究開発推進プログラム「シーズ発掘試験」.
セラミックハニカムを用いた高密度実装酸化物熱電発電モジュールの開発
2006.10~2007.02, 代表者:大瀧 倫卓, 九州大学, 科学技術振興機構
地域イノベーション創出総合支援事業 重点地域研究開発推進プログラム「シーズ発掘試験」.
500℃級排熱回収用熱電発電素子の開発
2003.02~2005.09, 代表者:大瀧 倫卓, 九州大学, 独立行政法人 科学技術振興機構
科学技術振興機構 重点地域研究開発促進事業
研究成果活用プラザ福岡 育成研究 大瀧プロジェクト
「500℃級排熱回収用熱電発電素子の開発」.
ナノブロックインテグレーションによる層状酸化物熱電材料の創製
2002.11~2008.03, 代表者:河本 邦仁, 名古屋大学, 独立行政法人 科学技術振興機構
科学技術振興機構 戦略的創造研究推進事業(CREST)
「エネルギーの高度利用に向けたナノ構造材料・システムの創製」研究領域(藤嶋 昭 領域代表)
「ナノブロックインテグレーションによる層状酸化物熱電材料の創製」
九大グループリーダー.
研究業績
主要著書
1. Michitaka Ohtaki, Oxide Thin Films, Multilayers and Nanocomposites, Springer, Chapter 7, Nanostructured Oxide Thermoelectric Materials with Enhanced Phonon Scattering, pp. 109-122., 2015.03.
2. 大瀧 倫卓, 熱電変換材料 実用・活用を目指した設計と開発 ~材料技術/モジュール化/フレキシブル化/実用例~, (株)情報機構, 第2章第3節, 最新の酸化物熱電変換材料の構造・物性とモジュール化, pp.61-71., 2014.12.
3. 大瀧 倫卓, 化学便覧応用化学編第7版, 丸善出版, 14.2.4. 熱電変換材料, 2014.01.
4. 大瀧 倫卓, サーマルマネジメント~余熱・排熱の制御と有効利用~, (株)エヌ・ティー・エス, 第3編第1章第1節1.2, 排熱回収用熱電材料の開発動向, pp. 375-388., 2013.04.
5. 大瀧倫卓, エネルギーハーベスティング技術の最新動向, シーエムシー出版, pp.147-163, 2010.10.
6. 日本熱電学会編, 熱電変換技術ハンドブック, (株)エヌ・ティー・エス, 「熱電材料としての酸化物」pp. 204-213, 2008.12.
7. 梶川武信、寺崎一郎、大瀧倫卓、他27名, 熱電変換システムの高効率化・高信頼性化技術, 技術情報協会, 第2節, pp. 28-45., 2006.09.
8. 日本セラミックス協会・日本熱電学会編, 熱電変換材料, 日刊工業新聞社, pp. 163-169, 2005.10.
9. Ed. D. M. Rowe, Thermoelectrics Handbook: macro to nano, CRC Press, ISBN: 0-8493-2264-2, pp.35-1〜35-15, 2006.01.
10. Ed. K. Koumoto, I. Terasaki, N. Murayama, Oxide Thermoelectrics, Research Signpost, ISBN 81-7736-100-7, pp. 159-180., 2002.12.
主要原著論文
1. Bui Duc LONG, Le Hong THANG, Nguyen Hong HAI, Koichiro SUEKUNI, Katsuaki HASHIKUNI, TRAN Quang Minh Nhat, Wojciech KLICH, Michitaka OHTAKI, Thermoelectric Quaternary Sulfide Cu2+xZn1−xSnS4 (x = 0–0.3): Effects of Cu substitution for Zn, Materials Science and Engineering B, 10.1016/j.mseb.2021.115353, 272, 115353, 2021.07.
2. Yuta SHIMIZU, Koichiro SUEKUNI, Hikaru SAITO, Pierric LEMOINE, Emmanuel GUILMEAU, Bernard RAVEAU, Raju CHETTY, Michihiro OHTA, Toshiro TAKABATAKE, Michitaka OHTAKI, Synergistic Effect of Chemical Substitution and Insertion on the Thermoelectric Performance of Cu26V2Ge6S32 Colusite, Inorganic Chemistry, 10.1021/acs.inorgchem.1c01321, accepted for publication on 6 July 2021., 2021.07.
3. Rauf KHAN, Michitaka OHTAKI, Satoshi HATA, Koji MIYAZAKI, Reiji HATTORI, Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method, Nanomaterials, 10.3390/nano11061547, 11, 6, 1547 (10 pages), 2021.06.
4. Ahrong JEONG, Koichiro SUEKUNI, Michitaka OHTAKI, Byung Koog JANG, Thermoelectric Properties of In- and Ga-doped Spark Plasma Sintered ZnO Ceramics, Ceramics International, 10.1016/j.ceramint.2021.05.101, in press, available online 19 May 2021., 2021.05.
5. Nhat Quang Minh TRAN, Michitaka OHTAKI, Koichiro SUEKUNI, Rapid Synthesis of W18O49 via Reactive Spark Plasma Sintering with Controlled Anisotropic Thermoelectric Properties, Evergreen, 8, 2, accepted for publication on 16 May 2021., 2021.05.
6. Takashi HAGIWARA, Koichiro SUEKUNI, Pierric LEMOINE, Andrew R. SUPKA, Raju CHETTY, Emmanuel GUILMEAU, Bernard RAVEAU, Marco FORNARI, Michihiro OHTA, Rabih Al Rahal Al ORABI, Hikaru SAITO, Katsuaki HASHIKUNI, Michitaka OHTAKI, Key Role of d0 and d10 Cations for the Design of Semiconducting Colusites: Large Thermoelectric ZT in Cu26Ti2Sb6S32 Compounds, Chemistry of Materials, 10.1021/acs.chemmater.1c00872, 33, 9, 3449-3456, 2021.04.
7. Katsuaki HASHIKUNI, Koichiro SUEKUNI, Hidetomo USUI, Raju CHETTY, Michihiro OHTA, Toshiro TAKABATAKE, Michitaka OHTAKI, A Comparative Study of Thermoelectric Cu2TrTi3S8 (Tr = Co and Sc) Thiospinels: Enhanced Seebeck Coefficient via Electronic Structure Modification, Journal of Alloys and Compounds, 10.1016/j.jallcom.2021.159548, 871, 159548 (9 pages), 2021.03.
8. Wojciech KLICH, Michitaka OHTAKI, Thermoelectric Properties of Mo-doped Bulk In2O3 and Prediction of its Maximum ZT, Ceramics International, 10.1016/j.ceramint.2021.03.129, 47, 13, 18116-18121, 2021.03.
9. Sampad GHOSH, Sivasankaran HARISH, Michitaka OHTAKI, Bidyut Baran SAHA, Thermoelectric Figure of Merit Enhancement in Cement Composites with Graphene and Transition Metal Oxides, Materials Today Energy, 10.1016/j.mtener.2020.100492, 18, 100492 (6 pages), 2020.08.
10. Shinji HIRATA, Michitaka OHTAKI, Kosuke WATANABE, Highly Improved Thermoelectric Performance of Nb-doped SrTiO3 due to Significant Suppression of Phonon Thermal Conduction by Synergetic Effects of Pores and Metallic Nanoparticles, Ceramics International, 10.1016/j.ceramint.2020.07.085, 46, 16A, 25964-25969, 2020.07.
11. Anh Tuan Thanh Pham, Tuyen Anh Luu, Ngoc Kim Pham, Hanh Kieu Thi Ta, Truong Huu Nguyen, Dung Van Hoang, Hoa Thi Lai, Vinh Cao Tran, Jong Ho Park, Jae Ki Lee, Sungkyun Park, Ohtaki Michitaka, Su Dong Park, Hung Quang Nguyen, Thang Bach Phan, Multi-scale defects in ZnO thermoelectric ceramic materials co-doped with In and Ga, Ceramics International, 10.1016/j.ceramint.2020.01.084, 46, 8, 10748-10758, 2020.06, [URL], In this work, several X-ray and nuclear analysis techniques were used to examine ZnO materials co-doped with In and Ga, or IGZO materials. X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy revealed multi-scale defects in the materials. A nanoscale secondary Ga2Zn9O12 spinel phase, mesoscale grain boundaries, and atomic-scale lattice defects were detected. The lattice defects included oxygen vacancies, zinc vacancies, and complex defects. Positron annihilation spectroscopy and Doppler broadening spectroscopy provided evidence of interactions between charge carriers and defects sites, which explained the low thermal conductivities of the IGZO materials (κtotal ≈ 3.9 W/mK) at 773 K. This combination of X-ray and nuclear analytical techniques can be viewed as a novel approach for investigating the thermoelectric properties of materials with complex crystal structures that contain atomic-scale voids, nanoscale secondary phases, and mesoscale grain boundaries..
12. Dung Van HOANG, Anh Tuan Thanh PHAM, Hanh Kieu Thi TA, Truong Huu NGUYEN, Ngoc Kim PHAM, Lai Thi HOA, Vinh Cao TRAN, Michitaka OHTAKI, Quang Minh Nhat TRAN, Jong-Ho PARK, Jae-Ki LEE, Su-Dong PARK, Tae-Seong JU, Hongjun PARK, Sungkyun PARK, Thang Bach PHAN, Effects of Multi-scale Defects on the Thermoelectric Properties of Delafossite CuCr1-xMgxO2 Materials, Journal of Alloys and Compounds, 10.1016/j.jallcom.2020.156119, 844, 156119, 2020.06.
13. Takuya Tanimoto, Koichiro Suekuni, Taiki Tanishita, Hidetomo Usui, Terumasa Tadano, Taiga Kamei, Hikaru Saito, Hirotaka Nishiate, Chul Ho Lee, Kazuhiko Kuroki, Michitaka Ohtaki, Enargite Cu3PS4: A Cu–S-Based Thermoelectric Material with a Wurtzite-Derivative Structure, Advanced Functional Materials, 10.1002/adfm.202000973, 30, 22, 2000973, 2020.05, [URL], Compound semiconductors derived from ZnS (zincblende and wurtzite) with tetrahedral framework structures have functions for various applications. Examples of such materials include Cu–S-based materials with zincblende-derivative structures, which have attracted attention as thermoelectric (TE) materials over the past decade. This study illuminates superior TE performance in polycrystalline samples of enargite Cu3P1−xGexS4 with a wurtzite-derivative structure. The substitution of Ge for P dopes holes into the top of the valence band composed of Cu-3d and S-3p, whereby its multiband characteristic leads to a high TE power factor. Furthermore, a reduction in the grain size to 50–300 nm can effectively decrease phonon mean free paths, leading to low thermal conductivity. These features result in a dimensionless TE figure of merit ZT of 0.5 at 673 K for the x = 0.2 sample. Environmentally benign and low-cost characteristics of the constituent elements of Cu3PS4, as well as its high-performance thermoelectricity, make it a promising candidate for large-scale TE applications. Furthermore, this finding extends the development field of Cu–S-based TE materials to those with wurtzite-derivative structures..
14. Sampad Ghosh, Sivasankaran Harish, Michitaka Ohtaki, Bidyut Baran Saha, Enhanced figure of merit of cement composites with graphene and ZnO nanoinclusions for efficient energy harvesting in buildings, Energy, 10.1016/j.energy.2020.117396, 198, 2020.05, [URL], In this work, we have reported the thermoelectric performance of graphene-zinc oxide hybrid cement composites for the first time. Nanostructured graphene and zinc oxide were incorporated into cement to increase the thermoelectric properties of cement composites. The as-received materials were blended, compressed, and subsequently cured at room temperature to make it bulk. On bulk samples, electrical conductivity, Seebeck coefficient, and thermal conductivity were measured. As a consequence of high electrical conductivity and the Seebeck coefficient, the composites exhibited a high value of thermoelectric efficiency. The maximum figure of merit (ZT) of 0.01 is obtained when the contents of graphene and ZnO are 10 wt%, respectively, by mass of cement. This ZT is the highest reported to date for the thermoelectric cement composites, a nearly 70% increase over the previous record with carbon based inclusions. High figure of merit is crucial for energy harvesting applications in future buildings..
15. Shinji Hirata, Michitaka Ohtaki, Simultaneous enhancement in the electrical conductivity and reduction in the lattice thermal conductivity leading to enhanced thermoelectric zt realized by incorporation of metallic nanoparticles into oxide matrix, Evergreen, 10.5109/2740934, 7, 1, 1-6, 2020.03, [URL], Nanoporous Fe3O4 composites containing metallic Cu nanoparticles were synthesized by reducing-leaching treatment of CuFe2O4 precursor. Thermoelectric properties of the composites sintered at 1270 ºC greatly improved compared with Fe3O4 without Cu, presumably due to a nanoporous structure and the Cu nanoparticles remaining in the Fe3O4 matrix after acid leaching. The electrical and thermal conductivity indicate that Cu in the matrix promotes the electron conduction and suppresses the phonon conduction, improving the dimensionless figure-of-merit, ZT..
16. Taiki Tanishita, Koichiro Suekuni, Hirotaka Nishiate, Chul Ho Lee, Michitaka Ohtaki, A strategy for boosting the thermoelectric performance of famatinite Cu3SbS4, Physical Chemistry Chemical Physics, 10.1039/c9cp06233e, 22, 4, 2081-2086, 2020.01, [URL], Famatinite Cu3SbS4 has attracted attention for its potential application in thermoelectric (TE) contexts. In this work, we report the impacts of co-substituting Ge and P for Sb on TE properties. Melting and heat treatment methods were adopted to synthesize samples of Cu3Sb1-x-yGexPyS4 (x ≤ 0.4, y ≤ 0.3). In this system, Ge functioned as an acceptor for doping a hole to the valence band, which led to enhancement of the TE power factor. Contrastingly, P barely altered the electronic structure. Furthermore, both Ge and P acted as point defects, which effectively decreased lattice thermal conductivity. The combined effects of the co-substitution gave rise to an enhanced dimensionless figure of merit, ZT, of 0.67 at 673 K..
17. Sampad Ghosh, Sivasankaran Harish, Kaiser Ahmed Rocky, Michitaka Ohtaki, Bidyut Baran Saha, Graphene enhanced thermoelectric properties of cement based composites for building energy harvesting, Energy and Buildings, 10.1016/j.enbuild.2019.109419, 202, 2019.11, [URL], Cement based thermoelectric materials can convert the available ambient heat absorbed by the building surfaces in summer into electrical energy. These materials can have an impact on the improvement of indoor climate of buildings, reduction of energy consumption and energy harvesting applications especially in the urban areas. In this paper, the thermoelectric properties of cement based composites with graphene nanoplatelets (GNP) inclusions were reported for the first time. GNP-cement mixtures were prepared by planetary ball milling and compressed subsequently to form bulk composites. We report the maximum electrical conductivity of 16.2 Scm−1 and Seebeck coefficient of +34.0 µVK−1 in this work. Hall measurement was performed to determine the material type and carrier concentration. It was found that all specimen exhibit p-type semiconductor behavior. Thermal diffusivity measurements were carried out using laser flash measurement technique. The highest figure of merit 0.44 × 10−3 was achieved at about 70 °C. Enhanced thermoelectric properties of graphene nanoplatelets cement based composites have a promising prospect in the urban heat island effect alleviation, thus saving electricity consumption and energy harvesting..
18. Koichiro Suekuni, Hidetomo Usui, Siying Qiao, Katsuaki Hashikuni, Tatsuya Hirano, Hirotaka Nishiate, Chul Ho Lee, Kazuhiko Kuroki, Kosuke Watanabe, Michitaka Ohtaki, Electronic structure and thermoelectric properties of Sn1.2-xNbxTi0.8S3 with a quasi-one-dimensional structure, Journal of Applied Physics, 10.1063/1.5093183, 125, 17, 2019.05, [URL], We report the electronic structure and thermoelectric properties of a tin titanium trisulfide, Sn1.2Ti0.8S3. The crystal structure is composed of infinite "ribbons" of double edge-sharing (Sn4+/Ti4+)S6 octahedra capped by Sn2+. First-principles calculations predict a nearly unidirectional transport of electrons along the ribbon axis for a single crystal and the existence of lone-pair electrons on Sn2+. Experiments on polycrystalline pressed samples demonstrate that Sn1.2Ti0.8S3 exhibits semiconducting temperature dependence of electrical resistivity and a large negative Seebeck coefficient at room temperature. Substitution of Nb5+
for Sn4+ at the octahedral sites increases the electron carrier concentration, leading to an enhancement of the thermoelectric power factor. Anisotropy in the electronic properties is weak because of a weak orientation of the ribbon axis of crystallites in the pressed sample. The lattice thermal conductivity is less than 1 W K-1m-1 for the pristine and substituted samples, which is attributed to weak bonding between the ribbons via the lone-pair electrons of Sn2+ and to random occupation of S4+, Ti4+, and Nb5+ at the octahedral sites..
19. Koichiro Suekuni, Yuta Shimizu, Eiji Nishibori, Hidetaka Kasai, Hikaru Saito, Daichi Yoshimoto, Katsuaki Hashikuni, Yohan Bouyrie, Raju Chetty, Michihiro Ohta, Emmanuel Guilmeau, Toshiro Takabatake, Kosuke Watanabe, Michitaka Ohtaki, Atomic-scale phonon scatterers in thermoelectric colusites with a tetrahedral framework structure, Journal of Materials Chemistry A, 10.1039/c8ta08248k, 7, 1, 228-235, 2019.01, [URL], Copper-based chalcogenides with tetrahedral framework structures have been attracting increasing attention as environmentally friendly thermoelectric materials. A representative group of such thermoelectric chalcogenides is the Cu 26 A 2 M 6 S 32 (A = V, Nb, Ta; M = Ge, Sn) family of colusites, which exhibit low electrical resistivity, a large Seebeck coefficient, and low thermal conductivity; these properties are necessary for efficient thermal-to-electronic energy conversion. Here, we show the impact of crystal structure on the lattice thermal conductivity of colusite with A = Nb, M = Sn. The crystal structure can be modified by controlling the cationic compositions and the deficiency in the sulfur content as Cu 26-x Nb 2 Sn 6+x S 32-δ . The Cu/Sn ratio is found to be the key parameter for exsolution into distinct phases with ordered and disordered arrangements of cations. For the ordered-structure phase, sulfur sublimation induces atomic-scale defects/disordered states including interstitial defects, anti-site defects, and site splitting, which function as strong phonon scatterers, and the lowest lattice thermal conductivity of ∼0.5 W K -1 m -1 is achieved for the modified ordered structure. This finding provides a simple approach to modifying the crystal structure of thermoelectric chalcogenides via the loss of anions to reduce their lattice thermal conductivity..
20. Katsuaki Hashikuni, Koichiro Suekuni, Hidetomo Usui, Raju Chetty, Michihiro Ohta, Kazuhiko Kuroki, Toshiro Takabatake, Kosuke Watanabe, Michitaka Ohtaki, Thermoelectric Properties and Electronic Structures of CuTi2S4 Thiospinel and Its Derivatives: Structural Design for Spinel-Related Thermoelectric Materials, Inorganic Chemistry, 10.1021/acs.inorgchem.8b02955, 58, 2, 1425-1432, 2019.01, [URL], We report the preparations, thermoelectric and magnetic properties, and electronic structures of Cu-Ti-S systems, namely, cubic thiospinel c-Cu1-xTi2S4 (x ≤ 0.375), a derivative cubic and Ti-rich phase c-Cu1-xTi2.25S4 (x = 0.5, 0.625), and a rhombohedral phase r-CuTi2S4. All samples have the target compositions except for r-CuTi2S4, whose actual composition is Cu1.14Ti1.80S4. All of the phases have n-type metallic character and exhibit Pauli paramagnetism, as proven by experiments and first-principles calculations. The Cu and Ti deficiencies in c-Cu1-xTi2S4 and r-CuTi2S4, respectively, decrease the electron-carrier concentration, whereas the "excess" of Ti ions in c-Cu1-xTi2.25S4 largely increases it. For r-CuTi2S4, the reduced carrier concentration increases the electrical resistivity and Seebeck coefficient, leading to the highest thermoelectric power factor of 0.5 mW K-2m-1 at 670 K. For all of the Cu-Ti-S phases, the thermal conductivity at 670 K is 3.5-5 W K-1m-1, where the lattice part of the conductivity is as low as 1 W K-1m-1at 670 K. As a result, r-CuTi2S4 shows the highest dimensionless thermoelectric figure of merit ZT of 0.2. The present systematic study on the Cu-Ti-S systems provides insights into the structural design of thermoelectric materials based on Cu-M-S (M = transition-metal elements)..
21. Yulia Eka Putri, Suhana Mohd Said, Refinel Refinel, Michitaka Ohtaki, Syskri Syukri, Low Thermal Conductivity of RE-Doped SrO(SrTiO3)1 Ruddlesden Popper Phase Bulk Materials Prepared by Molten Salt Method, Electronic Materials Letters, 10.1007/s13391-018-0062-x, 1-7, 2018.04.
22. Katsuaki Hashikuni, Koichiro Suekuni, Kosuke Watanabe, Yohan Bouyrie, Michihiro Ohta, Michitaka Ohtaki, ToshiroTakabatake, Carrier Concentration Tuning in Thermoelectric Thiospinel Cu2CoTi3S8 by Oxidative Extraction of Copper, Journal of Solid State Chemistry, 10.1016/j.jssc.2017.12.031, 259, 5-10, 2018.03.
23. Kohei Mizuta, Michitaka Ohtaki, Crystal Structure and Thermoelectric Properties of β-Pyrochlore-Type Alkali Iron Tungsten Oxides with Cage-Like Structure, Journal of Electronic Materials, 10.1007/s11664-015-4179-5, 45, 3, 1695-1699, 2016.03.
24. Michitaka Ohtaki, Nanostructured oxide thermoelectric materials with enhanced phonon scattering, Oxide Thin Films, Multilayers, and Nanocomposites, 10.1007/978-3-319-14478-8_7, 107-122, 2015.01, [URL], Rapid progress in thermoelectric performance of oxide materials has been conducted virtually exclusively in Japan, resulting in more than ten times increase in the ZT values of oxides within the last two decades. This has caused a revolutionary change in the guiding principles of thermoelectric materials research, in which oxide materials had been disregarded as a potential candidate until early 1990s. Promising oxide thermoelectric materials having been discovered include CaMnO 3 -based perovskites, Al-doped ZnO, layered cobalt oxides represented by NaCo2O4 and Ca3Co4O9, and SrTiO 3 -related phases. This chapter reviews the current aspects of bulk oxide thermoelectric materials, and some strategies for selective reduction of the lattice thermal conductivity (selective phonon scattering) in bulk oxides are also discussed..
25. Li Han, Ngo Van Nong, Wei Zhan, Le Thanh Hung, Tim Holgate, Kazunari Tashiro, Michitaka Ohtaki, Nini Pryds, Søren Linderoth, Effects of morphology on the thermoelectric properties of Al-doped ZnO, RSC Advances, 4, 24, 12353-12361, 2014.02.
26. Tohru Sugahara, Michitaka Ohtaki, Katsuaki Suganuma, La doped effects on structure and thermoelectric properties of Sr2MnMoO6 double-perovskite oxides, Journal of Asian Ceramic Societies, 1, 3, 282-288, 2013.09.
27. Michitaka Ohtaki, So Miyaishi, Extremely Low Thermal Conductivity in Oxides with Cage-like Crystal Structure
, Journal of Electronic Materials, 10.1007/s11664-012-2382-1, 42, 2013.06.
28. Li Han, Ngo Van Nong, Le Thanh Hung, Nini Pryds, Michitaka Ohtaki, Søren Linderoth, The Influence of α- and γ-Al2O3 Phases on the Thermoelectric Properties of Al-doped ZnO
, Journal of Alloys and Compounds, 555, 291-296, 2013.04.
29. Nguyen Viet Long, Michitaka Ohtaki, Masayoshi Yuasa, Satoshi Yoshida, Taiga Kuragaki, Gao Minh Thi, Masayuki Nogami, Synthesis and Self-Assembly of Gold Nanoparticles by Chemically Modified Polyol Methods under Experimental Control, Journal of Nanomaterials, 2013, 793125, 2013.04.
30. Nguyen Viet Long, Masayuki Nogami, Cao Minh Thi, Michitaka Ohtaki, Experimental Evidences of Crystal Nucleation and Growth of Platinum Nanoparticles with Most Characteristic Roughness Heteromorphologies and Nanostructures from Homogeneous Solution, Journal of Advanced Microscopy Research, 7, 1-20, 2012.09.
31. Tohru Sugahara, Teppei Araki, Michitaka Ohtaki, Katsuaki Suganuma, Structure and Thermoelectric Properties of Double-perovskite Oxides: Sr2-xKxFeMoO6, Journal of the Ceramic Society of Japan, 120, 6, 211-216, 2012.06.
32. Nguyen Viet Long, Cao Minh Thi, Masayuki Nogami, Michitaka Ohtaki, Novel Issues of Morphology, Size, and Structure of Pt Nanoparticles in Chemical Engineering: Surface Attachment, Aggregation or Agglomeration, Assembly, and Structural Changes, New Journal of Chemistry, 10.1039/C2NJ40027H, 2012.06.
33. Nguyen Viet Long, Michitaka Ohtaki, Takashi Matsubara, Cao Minh Thi, Masayuki Nogami, New Experimental Evidences of Pt-Pd Bimetallic Nanoparticles with Core-Shell Configuration and Highly Fine-ordered Nanostructures by High-Resolution Electron Transmission Microscopy, The Journal of Physical Chemistry C, 116, 22, 12265-12274, 2012.06, In our facile synthesis method, poly(vinylpyrrolidone) protected Pt and Pt-Pd bimetallic nanoparticles with controllable polyhedral core-shell morphologies are precisely synthesized by the reduction of Pt and Pd precursors at a certain temperature in ethylene glycol and silver nitrate as structure-controlling agent. The Pt nanoparticles exhibited well-shaped polyhedral morphology with highly fine and specific nanostructures in the nanosized range of 20 nm. Important evidences of core-shell configurations of the Pt-Pd core-shell nanoparticles were clearly characterized by high-resolution transmission electron microscopy (HRTEM) measurements. The results of HRTEM images showed that the core-shell Pt-Pd nanoparticles in the nanosized range of 25 nm with polyhedral morphology were synthesized with the thin Pd shells of the nanosized range of about 3 nm in thickness as the atomic Pd layers grown on the as-prepared Pt cores in the nanosized range. The very interesting characterization of surface structure of Pt nanostructures and Pt-Pd core-shell nanostructures with surface defects were observed. The high-resolution TEM images of Pt-Pd bimetallic nanoparticles showed that the Frank-van-der Merwe and Stranski-Krastanov growth modes coexist in the nucleation and growth of the Pd shells on the as-prepared Pt cores. The lattice-fringe spacing was estimated as around 0.240 nm, which is assigned exactly to the lattice-fringe spacing of the {111} planes of the Pd metal shell observed. It is predicted that the FM growth becomes a more favorable growth mode compared to the SK growth in the formation of the very thin Pd shells of Pt-Pd core-shell nanoparticles. The experimental evidences of the deformations of lattice fringes and lattice-fringe patterns were found in polyhedral Pt nanoparticles as well as polyhedral Pt-Pd core-shell nanoparticles. The interesting re-nucleation and re-crystallization at their connections or their attachments of the as-prepared nanoparticles are found in a good lattice match. In addition, our novel ideas of the largest surface-area superlattices and suitable utilization of such large surface areas are proposed for next generations of various fuel cells with low cost. Finally, the products of as-prepared Pt-Pd core-shell nanoparticles can potentially utilized as highly efficient catalysts in the realization of polymer electrolyte membrane cell (PEMFC) and direct methanol fuel cell (DMFC) using the very low Pt loading with better cost effective design..
34. Tohru Sugahara, Ngo Van Nong, Michitaka Ohtaki, Structure and Thermoelectric Properties of Ca2-xSrxFeMoO6 (0 ≤ x ≤ 0.3) Double-perovskite Oxides, Materials Chemistry and Physics, 133, 2-3, 630-634, 2012.04.
35. Nguyen Viet Long, Nguyen Duc Chien, Tomokatsu Hayakawa, Takashi Matsubara, Michitaka Ohtaki, Masayuki Nogami, Sharp Cubic and Octahedral Morphologies of Poly(vinylpyrrolidone)-stabilised Platinum Nanoparticles by Polyol Method in Ethylene Glycol: Their Nucleation, Growth and Formation Mechanisms, Journal of Experimental Nanoscience, 7, 2, 133-149, 2012.03.
36. Michitaka Ohtaki, Kazuhiko Araki, Thermoelectric Properties and Thermopower Enhancement of Al-doped ZnO with Nanosized Pore Structure, Journal of the Ceramic Society of Japan, 119, 11, 813-816, 2011.11.
37. Nguyen Viet Long, Michitaka Ohtaki, Tong Duy Hien, Jalem Randy, Masayuki Nogami, A Comparative Study of Pt and Pt-Pd Core-shell Nanocatalysts, Electrochimica Acta, 56, 25, 9133-9143, 2011.10.
38. Nguyen Viet Long, Michitaka Ohtaki, Tong Duy Hien, Jalem Randy, Masayuki Nogami, Synthesis and Characterization of Polyhedral and Quasi-sphere Non-polyhedral Pt Nanoparticles: Effects of Their Various Surface Morphologies and Sizes on Electrocatalytic Activity for Fuel Cell Applications, Journal of Nanoparticle Research, 13, 10, 5177-5191, 2011.10.
39. Tohru Sugahara, Michitaka Ohtaki, Structural and Semiconductor-to-metal Transitions of Double-perovskite Cobalt Oxide Sr2-xLaxCoTiO6-d with Enhanced Thermoelectric Capability, Applied Physics Letters, 99, 6, 062107, 2011.08.
40. Nguyen Viet Long, Michitaka Ohtaki, Masayuki Nogami, Tong Duy Hien, Effects of Heat Treatment and Poly(vinylpyrrolidone) (PVP) Polymer on Electrocatalytic Activity of Polyhedral Pt Nanoparticles towards their Methanol Oxidation, Colloid and Polymer Science, 289, 12, 1373-1386, 2011.08.
41. Nguyen Viet Long, Tong Dui Hien, Toru Asaka, Michitaka Ohtaki, Masayuki Nogami, Synthesis and Characterization of Pt-Pd Nanoparticles with Core-shell morphology: Nucleation and Overgrowth of the Pd Shells on the as-prepared and Defined Pt Seeds, Journal of Alloys and Compounds, 509, 29, 7702-7709, 2011.07.
42. Nguyen Viet Long, Masaya Uchida, Jalem Randy, Hirohito Hirata, Nguyen Duc Chien, Michitaka Ohtaki, Masayuki Nogami, Synthesis and Characterization of Pt-Pd Alloy and Core-shell Bimetallic Nanoparticles for Direct Methanol Fuel Cells (DMFCs): Enhanced Electrocatalytic Properties of Well-shaped Core-shell morphologies and Nanostructures, International Journal of Hydrogen Energy, 36, 14, 8478-8491, 2011.07.
43. Nguyen Viet Long, Michitaka Ohtaki, Masaya Uchida, Randy Jalem, Hirohito Hirata, Nguyen Duc Chien, Masayuki Nogami, Synthesis and Characterization of Polyhedral Pt Nanoparticles: Their Catalytic Property, Surface Attachments, Self-aggregation and Assembly, Journal of Colloid and Interface Science, 359, 2, 339-350, 2011.07.
44. Ngo Van Nong, Nini Pryds, Soren Linderoth, Michitaka Ohtaki, Enhancement of the Thermoelectric Performance of p-Type Layered Oxide Ca3Co4O9+d Through Heavy Doping and Metallic Nanoinclusions, Advanced Materials, 23, 21, 2484-2490, 2011.06.
45. Ngo Van Nong, Syun-ichi. Yanagiya, Sonne Monica, Nini Pryds, Michitaka Ohtaki, High-Temperature Thermoelectric and Microstructural Characteristics of Cobalt-Based Oxides with Ga Substituted on the Co-Site, Journal of Electronic Materials, 40, 5, 716-722, 2011.05.
46. N. V. Nong, C.-J. Liu, M. Ohtaki, High Temperature Thermoelectric Properties of Late Rare Earth-doped Ca3Co4-xGaxO9+d
, J. Alloy Compd., 509, 977-981, 2011.01.
47. N. V. Nong, C.-J. Liu, M. Ohtaki, Improvement on the High Temperature Thermoelectric Performance of Ga-doped Misfit-layered Ca3Co4-xGaxO9+d (x = 0, 0.05, 0.1, and 0.2), J. Alloy Compd., 491, 1-2, 53-56, 2010.01.
48. M. Ohtaki, K. Araki, K. Yamamoto, High Thermoelectric Performance of Dually Doped ZnO Ceramics, Journal of Electronic Materials, 38, 1234-1238, 2009.06.
49. T. Sugahara, M. Ohtaki, T. Souma, Thermoelectric Properties of Double-perovskite Oxide Sr2-xMxFeMoO6 (M = Ba, La), J. Ceram. Soc. Jpn., 116 (12), 1278-1282, 2008.12.
50. T. Souma, D. Isobe, M. Ohtaki, Synthesis and Rietveld Analysis of New Thermoelectric Oxides F-doped Na1.6Co2O4, Trans. Mater. Res. Soc. Jpn., 33 (4), 897-901, 2008.06.
51. M. Ohtaki, R. Hayashi, K. Araki, Thermoelectric Properties of Sintered ZnO Incorporating Nanovid Structure: Influence of the Size and Number Density of Nanovoids, Proc. 26th Int. Conf. Thermoelectrics, pp. 112-116, 2008.04.
52. T. Souma, M. Ohtaki, K. Ohnishi, M. Shigeno , Y. Ohba, N. Nakamura, T. Shimozaki, Power Generation Characteristics of Oxide Thermoelectric Modules Incorporating Nanostructured ZnO Sintered Materials, Proc. 26th Int. Conf. Thermoelectrics, pp. 38-41, 2008.04.
53. T. Souma, M. Ohtaki, M. Shigeno, Y. Ohba, N. Nakamura, T. Shimozaki, Jointing Technique and Power Generation Characteristics of p-NaCo2O4/n-ZnO Oxide Thermoelectric Modules, Trans. Mater. Res. Soc. Jpn., 32(3), 701-704, 2007.06.
54. M. Ohtaki, R. Hayashi, Enhanced Thermoelectric Performance of Nanostructured ZnO: A possibility of Selective Phonon Scattering and Carrier Energy Filtering by Nanovoid Structure, Proc. 25th Int. Conf. Thermoelectrics, pp.276-279., 2006.11.
55. T. Souma, M. Ohtaki, M. Shigeno, Y. Ohba, N. Nakamura, T. Shimozaki, Fabrication and Power Generation Characteristics of p-NaCo2O4/n-ZnO Oxide Thermoelectric Modules, Proc. 25th Int. Conf. Thermoelectrics, pp.603-606., 2006.11.
56. Ngo Van Nong, Michitaka Ohtaki, Power factors of late rare earth-doped Ca3Co2O6 oxides, Solid State Communications, 10.1016/j.ssc.2006.05.033, 139, 5, 232-234, 2006.08, [URL], Polycrystalline samples of (Ca1-xRx)3Co2O6 with R = Gd, Tb, Dy and Ho at x = 0 - 0.1 were synthesized and the effects of rare earth substitution on their thermoelectric properties were investigated. In the high-temperature region, the rare earth substitution resulted in an increase in the Seebeck coefficients (S), and the S values increased with decreasing ionic radius of rare earth elements in the order Gd3+>Tb3+>Dy3+>Ho3+ . In contrast, the influence of rare earth substitution on the electrical resistivity was small. The high-temperature power factor was thereby improved by the late rare earth substitutions, particularly those with Ho3+ for Ca2+. For the Ho-doped samples (x ≤ 0.05), the power factor was significantly improved by increasing Ho concentration..
57. N. V. Nong, M. Ohtaki, High-temperature Thermoelectric properties of Late Rare Earth-doped Ca3Co2O6, Trans. Mater. Res. Soc. Jpn., 31(2), 399-402, 2006.06.
58. H. Hirobe, M. Ohtaki, Enhanced Phonon Scattering by Oxygen Defects in Metal Oxides, Trans. Mater. Res. Soc. Jpn., 31(2), 403-406., 2006.06.
59. Takeshi Souma, Michitaka Ohtaki, Synthesis and Rietveld analysis of Zn4 - XCdxSb 3 bulk crystals in the Zn-rich region, Journal of Alloys and Compounds, 10.1016/j.jallcom.2005.06.062, 413, 1-2, 289-297, 2006.03, [URL], A series of nine bulk crystals of the Zn4 - xCd xSb3 compounds (x = 0-2.00 with 0.25 step) has been successfully synthesized and the detailed crystal structure has been refined by powder XRD study using the Rietveld method including the quantitative analysis. The substitution limit of the Cd atoms for the Zn4 - xCd xSb3 system has been extended to x = 2.00 by employing the vacuum casting method without annealing. The purities and densities of the bulk crystals exceeded approximately 96 mass% and 95% of XRD density, respectively. The lattice parameters of the a and c-axes in the system increase linearly with increasing Cd content x with obeying the Vegard law..
主要総説, 論評, 解説, 書評, 報告書等
1. Michitaka Ohtaki, Recent Aspects of Oxide Thermoelectric Materials for Power Generation from Mid-to-high Temperature Heat Source, Journal of the Ceramic Society of Japan, 119 (11), 770-775, 2011.11.
2. 大瀧倫卓, 熱-電気直接エネルギー変換のための酸化物熱電材料, 九州大卓グローバルCOEプログラム新炭素資源学ニューズレター, 2010.04.
3. 大瀧倫卓, 熱電酸化物セラミックスのナノ構造制御と熱電特性, 電気学会誌, 2008.05.
4. 大瀧倫卓, 熱エネルギーを電気に変えるセラミックス -新しい酸化物熱電変換材料の開発-, ペトロテック, 30 (9), 690-696, 2007.09.
5. 大瀧倫卓, 新しい熱電変換材料としての金属酸化物 −層状コバルト酸化物を中心に−, 月刊EcoIndustry, 10 (10), 13-20, 2005.10.
6. 大瀧倫卓, セラミックスの熱電的性質とその測定法, セラミックス, 40 (1), 39-46, 2005.01.
主要学会発表等
1. 大瀧倫卓, 組成とナノ構造の制御による酸化物サーモエレクトロニクスの開拓, 日本セラミックス協会2021年年会, 2021.03.
2. 大瀧倫卓, ナノコンポジット化による酸化物熱電変換材料の高性能化, 電気化学会九州支部2021年度春季特別講演会, 2021.03.
3. Michitaka Ohtaki, Shinji Hirata, Kosuke Watanabe, Koichiro Suekuni, Enhanced Thermoelectric Performance of Porous SrTiO3 with Exsolved Ni Nanoparticles, Pacific Rim Meeting on Electrochemical & Solid-State Science (PRiME2020), 2020.10.
4. 大瀧倫卓、平田慎治、渡邊厚介, Niナノ粒子を溶離析出したNbドープSrTiO3焼結体の熱電性能, 第17回日本熱電学会学術講演会(TSJ2020), 2020.09.
5. 西崎寛基、大瀧倫卓、末國晃一郎, 最も複雑な結晶構造を持つ酸化物Mo2P4O15のフォノン熱伝導, 第17回日本熱電学会学術講演会(TSJ2020), 2020.09.
6. 末國晃一郎、藤啓太、橋國克明、穴澤卯進、西当弘隆、李哲虎、大瀧倫卓, 室温熱電材料α-MgAgSbのホットプレスによる焼結体作製条件の検討, 第17回日本熱電学会学術講演会(TSJ2020), 2020.09.
7. 藤啓太、末國晃一郎、橋國克明、穴澤卯進、西当弘隆、李哲虎、大瀧倫卓, 室温熱電材料α-MgAgSbの溶融法による合成条件の検討, 第17回日本熱電学会学術講演会(TSJ2020), 2020.09.
8. 萩原岳志、末國晃一郎、橋國克明、Chetty Raju、太田道広、大瀧倫卓, 新規な高性能熱電硫化物Cu26Ti2Sb6−xGexS32, 第17回日本熱電学会学術講演会(TSJ2020), 2020.09.
9. 橋國克明、末國晃一郎、臼井秀知、Chetty Raju、太田道広、高畠敏郎、大瀧倫卓, 硫化スピネルCu2Ti4S8の電子構造制御によるゼーベック係数の増大, 第17回日本熱電学会学術講演会(TSJ2020), 2020.09.
10. 大瀧倫卓, 酸化物熱電変換材料の挑戦と展望, 賢材研究会2019年度賢材シンポジウム, 2020.03.
11. 大瀧倫卓, 組成とナノ構造の制御による酸化物サーモエレクトロニクスの開拓〜バルク酸化物における熱・電子輸送の実験的探究と新規分野開拓〜, 日本セラミックス協会2020年年会, 2020.03.
12. Michitaka Ohtaki, Shinji Hirata, Koichiro Suekuni, High Thermoelectric Performance of Porous Nb- and Ni-doped SrTiO3 Containing Highly Dispersed Exsolved Ni Nanoparticles, The 36th International Japan-Korea Seminar on Ceramics (J-K Ceramics 36), 2019.11.
13. Michitaka Ohtaki, Biomimetic Self-assembly Synthesis of Highly Regulated Single-nm Thick Layered Oxides and their Physicochemical Properties【招待講演】, The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13)、2019年10月27〜31日、沖縄コンベンションセンター(沖縄県宜野湾市), 2019.10, A highly regulated superlattice structure consisting of two-dimensional titanium oxide of ca. 1.5 nm in thickness with a d-spacing of 3 - 4 nm was synthesized in an aqueous solution by using bilayer micelles of sodium dodecylphosphate (SDP) surfactant as an organic molecule for a self-assembly template. A powder XRD study revealed that the product showed only (00l) diffractions in the low-2θ region, which are characteristic of a lamellar structure with a d001 spacing of ca. 4 nm. Moreover, hydrothermal (HT) post-treatment at 120 °C in distilled water markedly sharpened the (00l) diffractions, suggesting a substantial improvement in the spatial regularity of the layered structure. Precise temperature control of the solutions during the mixing and aging was revealed to be crucial to obtain highly regulated superlattice-like layered nanostructure. The optical absorption edge of the superlattice samples showed a large blue-shift of compared to that of bulk TiO2, suggesting an electron confinement effect in the titanium oxide layers.
Au ions were intercalated by using a phase-transfer catalyst into the hydrophobic interior of the bilayer micelles interleaving the TiO2 layers, and were subsequently reduced to obtain Au nanoparticles. The samples thus prepared showed an absorption peak in the visible light region and exhibited higher photocatalytic activity compared with layered TiO2 without Au as well as commercial TiO2 (P-25). It demonstrated that the Au nanoparticles enhanced the visible light photocatalytic activity of the layered TiO2 with the superlattice structure.
Fe-based oxide superlattice with presumably amorphous oxide framework was also biomimetically synthesized with the SDP micelles as the self-assembly template followed by the HT post-treatment (Fig. 1, Sample A). Whereas the low-angle (00l) diffractions disappeared after calcination at 350 °C (Sample B), the calcined samples immersed in an SDP aqueous solution successfully recovered the (00l) diffractions assigned to the superlattice structure (Sample C), indicating that the highly regulated layered structure once collapsed was reconstructed by the SDP molecules. These results also strongly suggest that the two-dimensionality of each oxide layer remained intact even after the calcination. It was also revealed that the bandgap energy of the samples alternatingly and reversibly switches between ca. 3.0 and 3.5 eV with the calcination/reconstruction cycles, implying that the disordering/reordering of the superlattice structure is responsible for the switching of the bandgap energy..
14. Sasikan Maneeyom, Koichiro Suekuni, Michitaka Ohtaki, Synthesis and Thermoelectric Properties of β-pyrochlore Oxide CsW2-xRuxO6, The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13)、2019年10月27〜31日、沖縄コンベンションセンター(沖縄県宜野湾市), 2019.10.
15. Nhat Quang Minh Tran, Koichiro Suekuni, Michitaka Ohtaki, Anisotropic Thermoelectric Properties of W18O49 Prepared by SPS, The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13)、2019年10月27〜31日、沖縄コンベンションセンター(沖縄県宜野湾市), 2019.10.
16. Wojciech Klich, Koichiro Suekuni, Michitaka Ohtaki, Thermoelectric Performance of Mo-doped bulk In2O3, The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13)、2019年10月27〜31日、沖縄コンベンションセンター(沖縄県宜野湾市), 2019.10.
17. Michitaka Ohtaki, Shinji Hirata, Koichiro Suekuni, Thermoelectric Performance of Porous Nb- and Ni-doped SrTiO3 Containing Ni Nanoparticles Exsolved by Reducing Post-treatment, The 13th Pacific Rim Conference of Ceramic Societies (PACRIM13)、2019年10月27〜31日、沖縄コンベンションセンター(沖縄県宜野湾市), 2019.10.
18. Michitaka Ohtaki, Shinji Hirata, Koichiro Suekuni, High Thermoelectric Performance of Reduced Nb-doped SrTiO3 Containing Exsolved Ni nanoparticles, 17th European Conference on Thermoelectrics (ECT2019), 2019.09.
19. 橋國克明、末國晃一郎、Chetty Raju、太田道広、高畠敏郎、大瀧倫卓, 硫化スピネルCu2FeTi3S8の結晶構造と熱電物性に対するCu欠損効果, 第16回日本熱電学会学術講演会(TSJ2019), 2019.09.
20. 谷下太基、末國晃一郎、西当弘隆、李哲虎、大瀧倫卓, ファマチナイトCu3Sb1-x-yGexPyS4の高い熱電性能, 第16回日本熱電学会学術講演会(TSJ2019), 2019.09.
21. 谷本拓哉、谷下太基、末國晃一郎、臼井秀知、西当弘隆、李哲虎、黒木和彦、大瀧倫卓, エナーガイトCu3PS4におけるPのGe置換によるキャリア濃度制御, 第16回日本熱電学会学術講演会(TSJ2019), 2019.09.
22. 清水裕太、末國晃一郎、Chetty Raju、太田道広、高畠敏郎、大瀧倫卓, コルーサイトCu26V2Si6S32の合成とキャリア濃度制御, 第16回日本熱電学会学術講演会(TSJ2019), 2019.09.
23. Michitaka Ohtaki, Hideaki Fujiwara, Kosuke Watanabe, Koichiro Suekuni, Ultra-low Lattice Thermal Conductivity of ZnO-based Thermoelectric Oxides, XXVIII International Materials Research Congress (IMRC2019)、2019年8月18〜23日、Cancun(Mexico), 2019.08.
24. Sasikan Maneeyom, Koichiro Suekuni, Michitaka Ohtaki, Thermoelectric properties of Ru-doped β-pyrochlore CsW2O6, The 38th International Conference on Thermoelectrics & the 4th Asian Conference on Thermoelectrics (ICT/ACT2019), 2019.06.
25. Nhat Q. M. Tran, Koichiro Suekuni, Michitaka Ohtaki, Nano-structured ReO3-type Building Blocks for Reduced Lattice Thermal Conductivity in High Temperature WO2.70 Penta-columnar Phase, The 38th International Conference on Thermoelectrics & the 4th Asian Conference on Thermoelectrics (ICT/ACT2019), 2019.06.
26. Takuya Tanimoto, Koichiro Suekuni, Hirotaka Nishiate, Chul-Ho Lee, Michitaka Ohtaki, Thermoelectric Properties of P- and Si-substituted Tetrahedrites, The 38th International Conference on Thermoelectrics & the 4th Asian Conference on Thermoelectrics (ICT/ACT2019), 2019.06.
27. Koichiro Suekuni, Hidetomo Usui, Siying Qiao, Katsuaki Hashikuni, Tatsuya Hirano, Hirotaka Nishiate, Chul-Ho Lee, Kazuhiko Kuroki, Kosuke Watanabe, Michitaka Ohtaki, Quasi-one-dimensional Electronic Structure and Low Thermal Conductivity in Sn1.2Ti0.8S3, The 38th International Conference on Thermoelectrics & the 4th Asian Conference on Thermoelectrics (ICT/ACT2019), 2019.06.
28. Katsuaki Hashikuni, Koichiro Suekuni, Hidetomo Usui, Raju Chetty, Michihiro Ohta, Kazuhiko Kuroki, Toshiro Takabatake, Kosuke Watanabe, Michitaka Ohtaki, Rhombohedral CuTi2S4: a thiospinel-derived thermoelectric material, The 38th International Conference on Thermoelectrics & the 4th Asian Conference on Thermoelectrics (ICT/ACT2019), 2019.06.
29. Michitaka Ohtaki, Anomalous Reduction of Lattice Thermal Conductivity in ZnO-based Thermoelectric Oxides with Extended Solid Solubility Limit on Binary Doping【招待講演】, E-MRS 2019 Spring Meeting/IUMRS-ICAM2019、2019年5月27〜31日、Congress & Exhibition Centre Acropolis, Nice(France), 2019.05, Zinc oxide has been one of the most promising n-type thermoelectric oxides with relatively large power factor values competitive to major non-oxide candidates such as skutterudites and clathrate compounds. However, a substantially high lattice thermal conductivity of ZnO has limited its ZT values below 0.7, despite a number of attempts to suppress the thermal conduction in the oxide.
Here we report an anomalously large reduction of the lattice thermal conductivity, ph, of ZnO doped with Al and Cu simultaneously. The ZnO samples doped with equimolar amounts (x at. % to Zn) of Al and Cu showed a significant peak shift in their XRD patterns, which has never been observed on single doping of Al or Cu. Moreover, the ph values of the samples at x = 8 was as low as 5 and 1.5 W/Km at room temperature and 800 °C, respectively. By comparing with those of Al-doped ZnO at x = 2, which are 40 and 8 W/Km at the corresponding temperatures, a 80% reduction of ph is overwhelming. A remarkable increase in the occupancy of Al in the 4-fold coordination was clearly confirmed by 27Al MAS solid state NMR, evidencing an extended solubility limit of Al into the Zn site in the presence of Cu as a co-dopant. It should also be noted that the ph value at 800 °C, 1.5 W/Km, is very close to the theoretical lower limit of 1.2 W/Km predicted for ZnO above room temperature..
30. 大瀧倫卓, 酸化物熱電変換材料の開発戦略と最新状況, 日本セラミックス協会九州支部春季特別講演会、2019年4月15日、北九州国際会議場(福岡県北九州市), 2019.04.
31. Michitaka Ohtaki, Drastically Suppressed Lattice Thermal Conductivity of ZnO-based Thermoelectric Oxides with Extended Solubility Limit on Binary Doping, The 43rd International Conference and Exposition on Advanced Ceramics and Composites (ICACC2019)、2019年1月26〜31日、Hilton Daytona Beach Oceanfront Resort, Daytona Beach, FL(USA), 2019.01, Zinc oxide has been one of the most promising n-type thermoelectric oxides with relatively large power factor competitive to major non-oxide candidates such as skutterudites and clathrate compounds. However, a quite high lattice thermal conductivity of ZnO has limited its ZT values below 0.7, despite a number of attempts to suppress the thermal conduction in the oxide. The ZnO samples doped with equimolar amounts (x at. % to Zn) of Al and Cu showed a significant peak shift in their XRD patterns, which has never been observed on single doping of Al or Ga. Moreover, the thermal conductivity of the samples at x = 8 was as low as 5 and 1.5 W/Km at room temperature and 800 °C, respectively. By comparing with the thermal conductivity of 40 and 8 W/Km for Al-doped ZnO at x = 2 at the corresponding temperatures, a drastic reduction of the thermal conductivity was obvious. An enhanced substitution of Zn with Al was clearly observed by 27Al MAS solid state NMR as enriched Al in the 4-fold coordination, evidencing an extended solubility limit of Al into the ZnO lattice in the presence of Cu as a co-dopant. It should also be noted that the value at 800 °C is very close to the theoretical lower limit of 1.2 W/Km for ZnO above room temperature..
32. Michitaka Ohtaki, Extremely Low Thermal Conductivity of ZnO Thermoelectric Oxide Doped with Al and Cu, The 5th Southeast Asia Conference on Thermoelectrics (SACT 2018), 2018.12.
33. 大瀧倫卓, 酸化物熱電半導体による未利用熱エネルギーの電力再生, 薄膜材料デバイス研究会第15回研究集会、2018年11月14〜15日、龍谷大学響都ホール校友会館(京都府京都市), 2018.11.
34. 大瀧倫卓, 酸化物による熱電元素戦略は可能か 〜酸化物熱電の難しさと期待〜, 第15回日本熱電学会学術講演会(TSJ2018), 2018.09.
35. 谷本拓哉、末國晃一郎、西当弘隆、李哲虎、大瀧倫卓, テトラヘドライトCu12Sb4S13の熱電物性に対するSiおよびP置換効果, 第15回日本熱電学会学術講演会(TSJ2018), 2018.09.
36. 平野達也、末國晃一郎、西当弘隆、李哲虎、大瀧倫卓, アージャイロダイト型化合物Cu8SiS6の結晶構造と熱電物性に対する元素置換効果, 第15回日本熱電学会学術講演会(TSJ2018), 2018.09.
37. 喬思瑩、末國晃一郎、西当弘隆、李哲虎、大瀧倫卓, 擬一次元構造をとるSn1.2Ti0.8S3とSn1.0Zr1.0S3の熱電物性に対するNb置換効果, 第15回日本熱電学会学術講演会(TSJ2018), 2018.09.
38. 清水裕太、末國晃一郎、斎藤光、吉本大地、西堀英治、笠井秀隆、Bouyrie Yohan、Chetty Raju、太田道広、橋國克明、高畠敏郎、大瀧倫卓, 熱電硫化銅鉱物コルーサイトの低熱伝導率を実現する結晶構造, 第15回日本熱電学会学術講演会(TSJ2018), 2018.09.
39. 橋國克明、末國晃一郎、臼井秀知、Chetty Raju、太田道広、黒木和彦、高畠敏郎, 硫化スピネルCu2Ti4S8の結晶構造と電子構造および熱電物性に対するCu欠損効果, 第15回日本熱電学会学術講演会(TSJ2018), 2018.09.
40. 渡邊厚介、松崎彰剛、末國晃一郎、大瀧倫卓, ボトムアップ合成によるSrTiO3/TiNナノ複合構造体の形成とその熱・電気輸送挙動, 日本セラミックス協会第31回秋季シンポジウム, 2018.09.
41. 平田慎治、大瀧倫卓、渡邊厚介、末國晃一郎, 金属ナノ粒子と細孔を共存させた酸化物系ナノコンポジット熱電材料の合成, 日本セラミックス協会第31回秋季シンポジウム, 2018.09.
42. Michitaka Ohtaki, Hideaki Fujiwara, Kosuke Watanabe, Koichiro Suekuni, Anomalously Low Thermal Conductivity of ZnO Along with Extended Solubility Limit of Al+Cu Binary Doping, Materials Challenges in Alternative and Renewable Energy 2018 (MCARE2018), 2018.08.
43. Shinji Hirata, Michitaka Ohtaki, Kosuke Watanabe, Koichiro Suekuni, Synthesis and Thermoelectric Properties of Oxide Nanocomposites Containing Metal Nanoparticles Formed by Exsolution Reaction, The 37th International and 16th European Conference on Thermoelectrics (ICT/ECT2018), 2018.07.
44. Tatsuya Hirano, Koichiro Suekuni, Katsuaki Hashikuni, Hirotaka Nishiate, Chul-Ho Lee, Toshiro Takabatake, Michitaka Ohtaki, Effects of Se Substitution on the Thermoelectric Properties of (SnS)1.2(TiS2)n (n = 1, 2), The 37th International and 16th European Conference on Thermoelectrics (ICT/ECT2018), 2018.07.
45. Michitaka Ohtaki, Hideaki Fujiwara, Kosuke Watanabe, Koichiro Suekuni, Extended Solubility Limit of ZnO on Binary Doping Leading to Anomalously Low Thermal Conductivity, The 37th International and 16th European Conference on Thermoelectrics (ICT/ECT2018), 2018.07.
46. Michitaka Ohtaki, Nanostructure Engineering in Oxide Thermoelectric Materials, 3rd Global Congress & Expo on Materials Science & Engineering, 2018.06.
47. Michitaka Ohtaki, Development of Oxide Ceramics for Thermoelectric Power Generation Applications, 42nd International Conference and Expo on Advanced Ceramics and Composites (ICACC2018), 2018.01.
48. Michitaka Ohtaki, Ultra-low Thermal Conductivity in Oxides with Rattler-in-a-Cage Crystal Structure Promising for High-temperature Thermoelectric Conversion, TThe 6th International Symposium on Advanced Ceramics and Technology for Sustainable Energy Applications toward a Low Carbon Society (ACTSEA 2017), 2017.11.
49. Michitaka Ohtaki, Self-assembly Synthesis and Physicochemical Properties of Highly Regulated Layered Oxides by Two-dimensionally Confined Growth in Single-nanometer Thickness
, The 6th International Workshop on Nanotechnology and Application (IWNA 2017), 2017.11.
50. Michitaka Ohtaki, Nanostructure Engineering in Oxide Thermoelectric Materials for Higher Energy Efficiency, The 13th International Conference on Ecomaterials (ICEM13), 2017.11.
51. Michitaka Ohtaki, Rattling Phenomena in Oxides for Enhanced Phonon Scattering, Workshop on Advanced Materials and Principles to Develop Viable Thermoelectrics and Advanced Thermal Management, 2017.09.
52. 峯一貴、渡邊厚介、末國晃一郎、大瀧倫卓, Auナノ粒子を導入したAl:ZnOナノコンポジットの構造と熱電特性, 第14回日本熱電学会学術講演会(TSJ2017), 2017.09.
53. 松崎彰剛、渡邊厚介、末國晃一郎、大瀧倫卓, SrTiO3/TiNコアシェル構造ナノ粒子の合成と熱電ナノコンポジット化, 日本セラミックス協会第30回秋季シンポジウム, 2017.09.
54. Michitaka Ohtaki, Kohei Mizuta, Koichiro Suekuni, Ultra-low Thermal Conductivity in β-Pyrochlore-type Oxides, 36th International Conference on Thermoelectrics (ICT2017), 2017.08.
55. Katsuaki Hashikuni, Koichiro Suekuni, Kosuke Watanabe, Bouyrie Yohan, Michihiro Ohta, Michitaka Ohtaki, and Toshiro Takabatake, Carrier Density Tuning in Cu2CoTi3S8 by Oxidative Extraction of Cu, 36th International Conference on Thermoelectrics (ICT2017), 2017.08.
56. Michitaka Ohtaki, Nanostructure Engineering for High-performance Oxide Thermoelectric Materials, 3rd World Congress on Materials Science & Engineering (Materials Science & Engineering), 2017.08.
57. 大瀧倫卓, エネルギー効率向上技術としての酸化物セラミックス熱電変換材料, 日本セラミックス協会第51回基礎科学部会セミナー, 2017.07.
58. Michitaka Ohtaki, Nanostructure Engineering in Oxide Ceramics for High Temperature Thermoelectric Energy Conversion
, 15th Conference & Exhibition of the European Ceramic Society (ECerS2017), 2017.07.
59. Michitaka Ohtaki, Thermoelectric Power Generation ― from fundamentals to applications with a demo of how to generate electricity , The Third International Workshop on Nano Materials for Energy Conversion (NMEC-3), 2017.05.
60. Michitaka Ohtaki, Crystal and Nanostructure Engineering in Oxide Thermoelectric Materials for Waste Heat Recovery, The Third International Workshop on Nano Materials for Energy Conversion (NMEC-3), 2017.05.
61. Michitaka Ohtaki, Kohei Mizuta, and Koichiro Suekuni, Ultra-low Thermal Conductivity in β-Pyrochlore Oxides with a Rattler-in-a-Cage Crystal Structure, The 12th Pacific Rim Conference on Ceramic and Glass Technology (PacRim12), 2017.05.
62. 石橋史啓、大瀧倫卓, 極細Auナノワイヤの生成反応における条件依存性, 日本化学会第97春季年会(2017), 2017.03.
63. Michitaka Ohtaki, Nanostructure and Phonon Engineering in Oxide Thermoelectric Materials, TMS 2017 146th Annual Meeting and Exhibition, 2017.02.
64. Michitaka Ohtaki, Thermal Conductivity Reduction in Oxides for Thermoelectric Energy Conversion, The 33rd International Korea-Japan Seminar on Ceramics (K-J Ceramics 33), 2016.11.
65. Michitaka Ohtaki, Oxide Thermoelectric Materials for Waste Heat Energy Recuperation, Global Congress & Expo on Materials Science & Nanoscience (Materials Science-2016), 2016.10.
66. 渡邊厚介、小川敏史、大瀧倫卓, ZnO焼結体への金属ナノ粒子分散プロセスと熱電特性, 日本セラミックス協会第29回秋季シンポジウム, 2016.09.
67. 渡部啓、大瀧倫卓、戸村信雄、北岡賢治、篠崎泰夫, 酸化物セラミックスの相転移現象に伴う熱伝導率変化, 日本セラミックス協会第29回秋季シンポジウム, 2016.09.
68. 渡邊厚介、峯一貴、大瀧倫卓, Ag/ZnOナノコンポジットの形成と熱電特性, 第13回日本熱電学会学術講演会(TSJ2016), 2016.09.
69. 平田慎治、大瀧倫卓, 金属ナノ粒子/多孔質複合体の電子・フォノン伝導特性, 第13回日本熱電学会学術講演会(TSJ2016), 2016.09.
70. Michitaka Ohtaki, ZnO-based Oxide Thermoelectric Materials with Microstructure Control for Selective Phonon Scattering, Materials Challenges in Alternative & Renewable Energy Conference (MCARE) 2016, 2016.04.
71. 早野慎一、大瀧倫卓, 分子集合体鋳型法によるナノ2D 酸化鉄の合成とその特性, 日本セラミックス協会2016年年会, 2016.03.
72. 水田航平、大瀧倫卓, 三価金属元素を含むβ-パイロクロア型酸化物の熱電特性, 日本セラミックス協会2016年年会, 2016.03.
73. 渡邊厚介、大瀧倫卓, 液相前駆体法によるAg/ZnO 焼結体の微細構造と熱電特性, 日本セラミックス協会2016年年会, 2016.03.
74. Michitaka Ohtaki and Kohei Mizuta, Enhanced Phonon Scattering in Cage-Like Structure Oxides with Rattling Atoms, 2016 MRS Spring Meeting and Exhibit, 2016.03.
75. Michitaka Ohtaki, Oxide Materials with Ultra-low Lattice Thermal Conductivity, The EMN Meeting on Thermoelectric Materials, 2016.02.
76. Kosuke Watanabe and Michitaka Ohtaki, Thermoelectric Properties of Ag/ZnO Sintered Bodies Prepared from Soft-chemical Precursors, 2015 MRS Fall Meeting & Exhibit, 2015.12.
77. Kohei Mizuta and Michitaka Ohtaki, The Crystal Structures and Thermoelectric Properties of Defect Pyrochlore Oxides with Anharmonic Vibration, 2015 MRS Fall Meeting & Exhibit, 2015.12.
78. Michitaka Ohtaki, Yuki Iwano, and Taiga Kuragaki, Thermoelectric Performance of Multinary-doped ZnO with Enhanced Phonon Scattering, The 3rd International Renewable and Sustainable Energy Conference (IRSEC'15), 2015.12.
79. Michitaka Ohtaki, Recent Progress in Oxide Thermoelectric Materials with Microstructure Control for Selective Phonon Scattering, 14th International Union of Materials Research Societies- International Conference on Advanced Materials (IUMRS-ICAM2015), 2015.10.
80. 水田航平、大瀧倫卓, Fe-W-O系β-パイロクロア型酸化物の熱電特性, 第12回日本熱電学会学術講演会(TSJ2015), 2015.09.
81. 渡邊厚介、大瀧倫卓, 液相前駆体法によるAg/ZnO焼結体の合成と熱電特性, 第12回日本熱電学会学術講演会(TSJ2015), 2015.09.
82. 平田慎治、大瀧倫卓, 金属微粒子の選択溶出によるナノ多孔質酸化物の合成と熱物性, 第12回日本熱電学会学術講演会(TSJ2015), 2015.09.
83. 早野慎一、大瀧倫卓, 分子集合体鋳型法によるナノ層状酸化鉄の合成とそのソフト化学的挙動, 日本セラミックス協会第28回秋季シンポジウム, 2015.09.
84. 大瀧倫卓、倉垣大河, ZnO系酸化物熱電材料の微細構造と高温挙動, 日本セラミックス協会第28回秋季シンポジウム, 2015.09.
85. Michitaka Ohtaki, Taiga Kuragaki, Yuki Iwano, Kiyoshi Yamamoto , Selective Phonon Scattering in ZnO-based Bulk Thermoelectric Oxides


, Advanced Materials World Congress 2015 (AMWC2015), 2015.08.
86. Michitaka Ohtaki, ZnO-based Oxide Thermoelectric Materials: problems solved and unsolved yet, The 11th International Conference on Ceramic Materials and Components for Energy and Environmental Applications (CMCEE-11), 2015.06.
87. Michitaka Ohtaki and Taiga Kuragaki, Microstructure and Thermoelectric Properties of 
Ga/Cu-doped ZnO, 34th International Conference on Thermoelectrics/13th European Conference on Thermoelectrics (ICT/ECT2015), 2015.06.
88. Kohei Mizuta and Michitaka Ohtaki, Crystal structure and thermoelectric properties of β-pyrochlore-type alkali iron tungsten oxides with cage-like structure, 34th International Conference on Thermoelectrics/13th European Conference on Thermoelectrics (ICT/ECT2015), 2015.06.
89. Michitaka Ohtaki, Enhanced Phonon Scattering in Nanostructured Oxide Materials, XVI International Forum on Thermoelectricity, 2015.05.
90. Michitaka Ohtaki, Recent Aspects of Oxide Ceramic Materials for Thermoelectric Energy Conversion, BIT's 1st Annual World Congress of Smart Materials-2015 (WCSM-2015), 2015.03.
91. 大瀧 倫卓, 酸化物熱電変換材料を用いた未利用熱回収用発電モジュール, 日本鉄鋼協会第169回春季講演大会, 2015.03.
92. Michitaka Ohtaki, New Aspects of Oxide Ceramic Materials for Thermoelectric Energy Conversion, Energy, Materials, and Nanotechnology (EMN) Meeting on Ceramics, 2015.01.
93. Michitaka Ohtaki, Kohei Mizuta, Yuki Iwano, New Aspects in Oxide Thermoelectric Materials for Heat-to-Electricity Direct Energy Conversion, The 13th Eurasia Conference on Chemical Sciences (EuAsC2S-13), 2014.12.
94. Michitaka Ohtaki, Yuki Iwano, Enhanced Phonon Scattering and Carrier Compensation in Multinary-doped ZnO Thermoelectric Oxide, 2014 MRS Fall Meeting, 2014.12.
95. Michitaka Ohtaki, Self-assembly Synthesis of 2-D Semiconducting Oxide Nano-superlattice with Enhanced Photocatalytic Activity by Incorporation of Au Nanoparticles, The Second International Workshop on Nano Materials for Energy Conversion (NMEC-2), 2014.11, A highly regulated superlattice structure consisting of two-dimensional titanium oxide of ca. 1.5 nm in thickness with a d-spacing of 3 - 4 nm was synthesized in liquid phase using bilayer micelles of sodium alkylphosphate surfactant as an organic self-assembly template. A powder XRD study revealed that the product showed only (00l) diffractions in the low-2θ region, which are characteristic of a lamellar structure with a d001 spacing of ca. 4 nm. Moreover, hydrothermal (HT) post-treatment at 120 °C in distilled water markedly sharpened the (00l) diffractions, suggesting a substantial improvement in the spatial regularity of the layered structure. Precise temperature control of the solutions during the mixing and aging was revealed to be crucial to obtain highly regulated superlattice-like layered nanostructure after the HT treatment.
The optical absorption edge of the superlattice samples showed a large blue-shift of compared to that of bulk TiO2, which can be accounted for electron confinement effects within the titanium oxide layers.
Au ions were intercalated by using a phase-transfer catalyst into the hydrophobic interior of bilayer micelle template interleaving the TiO2 layers, and were subsequently reduced to obtain Au nanoparticles. The samples thus prepared showed an absorption peak in the visible light region and exhibited higher photocatalytic activity compared with layered TiO2 without Au as well as commercial TiO2 (P-25). It demonstrated that the Au nanoparticles enhanced the visible light photocatalytic activity of the layered TiO2 with the superlattice structure.
.
96. Michitaka Ohtaki, Oxide Thermoelectric Materials for Power Generation From Mid-to-High Temperature Unused Heat Energy, The 16th Cross Straits Symposium on Energy and Environmental Science and Technology(CSS-EEST16), 2014.11.
97. Michitaka Ohtaki, Taiga Kuragaki, Taketoshi Tomida, High-temperature Durability of doped ZnO on Thermal Cycling under Aerobic Conditions, IUMRS International Conference in Asia (IUMRS-ICA) 2014, 2014.08, Oxide materials are promising candidates for thermoelectric power generation from waste heat at mid-to-high temperatures. The n-type thermoelectric properties of Al-doped ZnO, ZT ~ 0.3 at 1273 K, were first reported by the authors in 19961). Recently, we have obtained the ZT values of ~0.55 and ~0.65 at around 1273 K for nanostructured Al-doped ZnO and dually doped ZnO with Al and Ga, respectively2,3). These results strengthen the opportunity of using polycrystalline ZnO for low-cost practical waste heat harvesting. However, controversial results reported by several research groups on the thermoelectric performance of Al-doped ZnO have caused argument on the candidacy of ZnO-based thermoelectric materials. Therefore, it is noteworthy to investigate the influences of temperature and atmosphere on the thermoelectric properties of Al-doped ZnO systematically.

In the present paper, thermoelectric properties of ZnO doped with Al and/or other transition metals are investigated by thermally cycling the samples under various atmospheres, particularly focusing on the possible changes in the electrical conductivity and Seebeck coefficient. Repeated cycling from room temperature to 1273 K is carried out to examine the high-temperature stability of the oxide in the oxidative and inert atmospheres. The thermogravimetric analysis is also carried out up to 1573 K in order to investigate the non-stoichiometry of the oxide and to determine the desorbing species in various atmospheres at high temperature.

The results of the thermal cycling up to 1273 K in air clearly showed that the electrical conductivity and Seebeck coefficient of Al-doped ZnO sintered in N2 certainly changed during the first heating (H1), causing a large hysteresis in the first cycle (H1+C1). However, strikingly, the properties measured on the second heating (H2) were identical to those observed on the first cooling (C1), and hence the data corrected on the second cycle (H2+C2) reproduced those on C1, showing no hysteresis in the second cycle. These results demonstrate that the first heating in air up to 1273 K stabilizes the electrical properties of Al-doped ZnO sintered in N2. The details and the upper limit of the stable temperature range will be discussed..
98. Michitaka Ohtaki, Kohei Mizuta, Enhanced Phonon Scattering in Oxides with “Rattling” Atoms in Oversized Cage Structure, The 33rd International Conference on Thermoelectrics (ICT2014), 2014.07, Oxide thermoelectric materials, which are highly durable at high temperature in air, non-toxic, low cost with minimal environmental impact, are apparently promising for recuperation of decentralized waste heat energy at the temperature range of > 400 °C, where all the non-oxide candidate materials will eventually be oxidized under aerobic conditions. Although strongly ionic characters of oxide materials has been regarded as an inherent disadvantage leading to low carrier mobility and high lattice thermal conductivity, it has been revealed that such disadvantages are not always the case with all oxides. Recent reports on reduced ferroelectric oxides [1] and cage-like structure oxides [2] are convincing that the simple picture of ionic compounds no longer holds for these oxides.
In this paper, some new aspects in metal oxides that show unconventionally enhanced phonon scattering will be highlighted in terms of their transport properties and crystal structures. In particular, β-pyrochlore oxides ABB’O6 (A = K, Rb, Cs) show lower lattice thermal conductivity with decreasing the mass and size of the A-site alkali cations, clearly evidencing that the larger size mismatch between the A-site cations and the surrounding oversized cage framework enhances the “rattling” motion of the A-site cations and thereby efficiently shortens the phonon mean free path more for the smaller A-site cations. As a consequence, the thermal conductivity of the oxide with the smallest A cation, KBB’O6, was revealed to be virtually the same with its theoretical minimum, κmin [3].
.
99. Michitaka Ohtaki, Kohei Mizuta, Enhanced Phonon Scattering in “Rattling” Oxides for Thermoelectric Energy Conversion, The 6th Forum on New Materials, CIMTEC 2014, 2014.06, Increasing energy demands in worldwide definitely require safer energy security options. Thermoelectric (TE) conversion is becoming more and more of vital importance for higher overall energy efficiency.
In terms of durability at high temperature in air, metal oxides are most attractive. Since the early 1990s, several oxide materials such as CaMnO3, ZnO, SrTiO3, NaCoO2, and Ca3Co4O9 have been reported to show a promising thermoelectric performance. However, strongly ionic characters and the light constituent element, oxygen, of metal oxides are apparently against the conventional guiding principles for higher ZT.
In this paper, we report the thermal and electrical properties of defect pyrochlore (β-pyrochlore) oxides AB2O6 with the “rattler-in-a-cage” structure, in which small A cations sit in an oversized cage-like crystal structure. Extremely shortened phonon mean free path with smaller A cations of in the oxides will be reported. Moreover, improvement in the electrical conduction in the B2O6 framework of the oxides will be discussed.
.
100. 大瀧 倫卓, 中高温域の廃熱回収を目的とした熱電発電モジュール, 日本鉄鋼協会第167回春季講演大会, 2014.03.
101. Michitaka Ohtaki, So Miyaishi, Kohei Mizuta, New Aspects in Oxide Thermoelectric Materials with Unconventionally Enhanced Phonon Scattering, 11th European Conference on Thermoelectrics (ECT 2013), 2013.11.
102. Michitaka Ohtaki, Yuki Iwano, Oxide Thermoelectric Materials Promising for Power Generation from Mid-to-High Temperature Waste Heat, The 2nd International Symposium on Inorganic and Environmental Materials (ISIEM 2013), 2013.10.
103. 水田 航平, 大瀧 倫卓, β-パイロクロア型酸化物AAl0.33Te1.67O6 (A=K, Rb, Cs)の熱電特性, 日本熱電学会第十回学術講演会(TSJ2013), 2013.09.
104. Michitaka Ohtaki, Oxide Materials with Unconventional Transport Properties Promising for Thermoelectrics, The 15th Asian Chemical Congress (15ACC),, 2013. 8. 19-23. , 2013.08.
105. Michitaka Ohtaki, Nanostructured Oxide Ceramics for Efficient Thermoelectric Energy Conversion, 12th International Conference on Ceramic Processing Science (12-ICCPS), 2013.08.
106. 倉垣 大河, 大瀧 倫卓, ZnO系酸化物の熱電物性の温度・雰囲気依存性に関する研究, 第50回化学関連支部合同九州大会, 2013.07.
107. 大瀧 倫卓, 富田 健稔, 倉垣 大河, High-temperature Stability of ZnO-based Thermoelectric Materials with Thermal Cycling under Aerobic Conditions, The 32nd International Conference on Thermoelectrics (ICT2013), 2013.07.
108. Li Han, Ngo Van Nong, La Than Hung, 田代 一成, Wei Zang, Tim Holgate, Nini Pryds, 大瀧 倫卓, Søren Linderoth, Thermoelectric Properties of Al-doped ZnO Synthesized from Different Precursor Morphologies, The 32nd International Conference on Thermoelectrics (ICT2013), 2013.07.
109. 大瀧 倫卓, Oxide Materials in Thermoelectrics: Beyond a Simple Picture of Ionic Compounds, The 10th Pacific Rim Conference on Ceramic and Glass Technology (PacRim10), 2013.06.
110. Michitaka Ohtaki, Recent Aspects of R&D for Next Generation Thermoelectric Materials, The 1st Symposium of Research and Education Center for Advanced Energy Materials, Devices, and Systems, 2013.03.
111. 吉田 諭史, 大瀧 倫卓, 鉄系層状酸化物CuFeO2におけるアニオン置換とその熱電物性, 第51回セラミック基礎科学討論会, 2013.01.
112. Michitaka Ohtaki, Oxide Materials for Mid-to-High Temperature 
Thermoelectric Energy Conversion, The 29th International Korea-Japan Seminar on Ceramics, 2012.11.
113. Michitaka Ohtaki, Oxide Thermoelectric Materials Promising for Heat-to-Electricity Direct Conversion from Mid-to-High Temperature Waste Heat, 2nd International Conference on Competitive Materials and Technology Processes (ic-cmtp2), 2012.10.
114. Michitaka Ohtaki, Yuki Iwano, So Miyaishi, Optimizing the Thermoelectric Properties of Oxide Materials: some case studies and strategies, IUMRS-International Conference on Electronic Materials (IUMRS-ICEM 2012), 2012.09.
115. 北崎 将士, 大瀧 倫卓, 分子集合体を鋳型としたナノ層状酸化チタンのAuナノ粒子複合化と光触媒特性, 
日本セラミックス協会第25回秋季シンポジウム, 2012.09.
116. Michitaka Ohtaki, Oxide Thermoelectric Materials with Bulk Nanocomposite Structures for Heat-to-Electricity Direct Conversion 
and Applicability of Self-assembly Low-dimensional Oxide Nanomaterials, First International Workshop on Nano Materials for Energy Conversion and Fuel Cell (NMEC-1), 2012.08.
117. Michitaka Ohtaki, So Miyaishi, Extremely Low Thermal Conductivity in Oxides with Cage-like Crystal Structure
, The 31st International Conference on Thermoelectrics 2012 (ICT-2012), 2012.07.
118. Michitaka Ohtaki, Yuki Iwano, Thermoelectric Properties and Impurity-related Heterogeneous Microstructure of Doped ZnO, 
2012 Spring Meeting of E-MRS, 2012.05.
119. Michitaka Ohtaki, Zinc Oxide as a Promising Material for Thermoelectric Power Generation Utilizing Wasted Heat Energy, The 12th International Confernce on Chemical Sciences (EuAsC2S-12), 2012.04, Increasing energy demands in worldwide definitely require safer energy security options. Moreover, the threat of the nuclear power plant disaster after the massive tsunami attack in Japan in March 2011 has obviously been making energy policies in Japan and many other countries shift more toward renewable energies. Thermoelectric power generation is one of the most promising energy options for better energy efficiency by recovering a huge amount of unused waste heat energy, which is currently unable to utilize and thus discarded.
Thermoelectric (TE) power generation directly converts heat (more strictly a temperature difference) to electricity by exploiting the thermoelectric effects in solid semiconductor materials. However, conventional TE materials such as Bi2Te3 and PbTe are unlikely to accomplish wide commercialization in our society because of their toxicity, poor heat resistance, and low abundance of the comprising elements. In terms of durability and stability at high temperature in air, oxide materials are obviously most attractive. Among them, ZnO [1,2] is one of the prospective n-type oxide thermoelectric materials showing a fairly high figure-of-merit, Z = S2σ/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, and κ is the thermal conductivity. In fact, the power factor, S2σ, is large enough for Al-doped ZnO to be competitive to conventional non-oxide materials such as PbTe and Si-Ge alloys. Nevertheless, the light constituting elements and strong interatomic bonding in ZnO results in a very high κ compared to conventional thermoelectric materials based on heavy elements, limiting the Z values relatively low [1,2].
In this paper, simultaneous doping of ZnO with two or more elements is investigated in order to reduce the lattice thermal conductivity, κph, a contribution of lattice vibration or phonons to the total thermal conductivity κ = κph + κel. Analyses of the carrier mobility and κph revealed that a selective reduction of κph with maintaining relatively high σ values (selective phonon scattering) would be operative in ZnO doped with Al and Ga [3]. Moreover, binary doping of Al and Cu resulted in further intense and anomalous reduction of κ. The phonon scattering will be discussed in terms of the phonon mean free path and nanostructure in the oxide with concerning the theoretical prediction of the lower limit of κ in ZnO.

References
[1] M. Ohtaki, T. Tsubota, K. Eguchi, H. Arai, J. Appl. Phys., 79, 1816-1818 (1996).
[2] T. Tsubota, M. Ohtaki, K. Eguchi, H. Arai, J. Mater. Chem., 7, 85-90 (1997).
[3] M, Ohtaki, K, Araki, K. Yamamoto, J. Electron. Mater., 38, 1234-1238 (2009)..
120. 大瀧倫卓, 宮石壮, かご状結晶構造を持つβ-パイロクロア型酸化物の特異的に低い熱伝導率, 日本セラミックス協会2012年年会, 2012.03.
121. 古庄真也, 大瀧倫卓, 秩序的なメソポーラス構造を持つ焼結体の作製と熱伝導, 日本セラミックス協会2012年年会, 2012.03.
122. Michitaka Ohtaki, Oxide materials for high-temperature thermoelectrics, Deutsche Physikalische Gesellschaft 2011 Spring Meeting, 2012.03.
123. Michitaka Ohtaki, Yuki Iwano, Thermal Conductivity Reduction and Thermoelectric Performance of ZnO with Multinary Doping
, The 36th International Conference & Exposition on Advanced Ceramics & Composites (ICACC 2012), 2012.01.
124. Michitaka Ohtaki, Self-assembly Synthesis of 2-dimensional Metal Oxide Superlattices and Their Optical and Electromagnetic Properties, 2nd Nano Today Conference, 2011.12.
125. 岩野勇輝, 大瀧倫卓,, 多元ドープしたZnO系酸化物の熱電特性, 日本セラミックス協会第24回秋季シンポジウム, 2011.09.
126. Michitaka Ohtaki, Yuki Iwano, Promising n-type Thermoelectric Performance of ZnO-based Oxides for Energy Harvesting, E-MRS 2011 Fall Meeting, 2011.09.
127. Michitaka Ohtaki, Goro Yamamoto, Yuki Iwano, Controlling Microstructure of Metal Oxides for Efficient Thermoelectric Materials for Energy Harvesting, 9th European Conference on Thermoelectrics, 2011.09.
128. 大瀧倫卓, ナノ複合構造による酸化物熱電変換材料の高性能化, 日本セラミックス協会第45回基礎科学部会セミナー, 2011.08.
129. 菅原徹, 大瀧倫卓, ダブルペロブスカイト酸化物 Sr2-xLaxCoTiO6-δの熱電特性と構造および金属-半導体転移, 第10回日本熱電学会学術講演会(TSJ2011), 2011.08.
130. Michitaka Ohtaki, Oxide Ceramics Promising for Thermoelectric Power Generation from Mid-to-high Temperature Waste Heat【招待講演・基調講演】, 9th Pacific Rim Conference on Ceramic and Glass Technology (PacRim9), 2011.07.
131. Ngo Van Nong, Nini Pryds, Soren Linderoth, Michitaka Ohtaki, Heavy Ions Doping Coupled with Metallic Nanoinclusions: An effective way to improve the thermoelectric performance of p-type layered cobalt oxide materials, The 30th International Conference on Thermoelectrics (ICT-2011), 2011.07.
132. Michitaka Ohtaki, Kiyoshi Yamamoto, Yuki Iwano, Thermoelectric Properties of ZnO with Multinary Doping, The 30th International Conference on Thermoelectrics (ICT-2011), 2011.07.
133. Michitaka Ohtaki, Kiyoshi Yamamoto, Yuki Iwano, Anomalous Thermal Conductivity Reduction in ZnO by Binary Doping for Thermoelectric Applications, 12th Conference of the European Ceramic Society (ECerS-XII), 2011.06.
134. Michitaka Ohtaki, Recent Development of Metal Oxides on Heat-to-electricity Direct Conversion for Recuperating Decentralized Waste Heat Energy【招待講演】, The 2011 Villa Conference on Energy and and Environmental Research (VCEER 2011), 2011.04.
135. Michitaka Ohtaki, So Miyaishi, Thermal and Electrical Properties of Defect Pyrochlore Oxides with Highly Mobile Cations in Cage-like Structure, 2011 MRS Spring Meeting, 2011.04.
136. 大瀧倫卓, 自己組織化によるナノ構造の構築と電磁気・エネルギー機能, 日本化学会第91春季年会, 2011.03.
137. 伊勢田幸範, 大瀧倫卓, 電解析出法による層状マンガン-コバルト酸化物超格子薄膜の自己組織合成, 日本セラミックス協会2011年年会, 2011.03.
138. Michitaka Ohtaki, Kiyoshi Yamamoto, Decoupling of Electrical and Thermal Conduction in Co-doped ZnO with Spontaneously Formed Nanocomposite Structure, 2010 International Congress of Pacific Basin Societies (PACIFICHEM2010), 2010.12.
139. Tohru Sugahara, Michitaka Ohtaki, Ken Kurosaki, Hiroaki Muta, Yuji Ohishi, Shinsuke Yamanaka, Structure and Thermoelectric Properties of La-doped Double-Perovskite Oxide Sr2CoTiO6, 2010 MRS Fall Meeting, 2010.11.
140. Tohru Sugahara, Michitaka Ohtaki, Ken Kurosaki, Hiroaki Muta, Yuji Ohishi, Shinsuke Yamanaka, Structure and Thermoelectric Properties of Double-Perovskite Oxides A2FeMoO6 and A2MnMoO6 with A-site substitution, The 3rd International Congress on Ceramics (ICC-3), 2010.11.
141. Michitaka Ohtaki, So Miyaishi, Thermal and Electrical Properties of Metal Oxides with Rattling Cations in Cage-like Structure, The 3rd International Congress on Ceramics (ICC-3), 2010.11.
142. Michitaka Ohtaki, Masatoshi Mori, Self-assembly Synthesis and Photocatalytic Properties of Layered Oxide Structure with Single-nm Thickness, The 3rd International Congress on Ceramics (ICC-3), 2010.11.
143. Michitaka Ohtaki, So Miyaishi, Synthesis and Transport Properties of Metal Oxides with Cage-like Structure Containing “Rattling” Cations, The 7th International Conferences on Inorganic Materials, 2010.09.
144. Michitaka Ohtaki, Kiyoshi Yamamoto, Electrical and Thermal Transport Properties of ZnO Thermoelectric Oxide Doped with Al and Ga, The 12th International Conferences on Modern Materials & Technologies (CIMTEC2010) / 5th Forum of New Materials, 2010.06.
145. Tohru Sugahara, Michitaka Ohtaki, Influence of Selective Site Substitution on the Thermal Conductivity of Single- and Double-perovskite Oxides, The 29th International Conference on Thermoelectrics, 2010.06.
146. Ngo Van Nong, S. Yanagiya, J. Xua, S. Monica, Nini Pryds, Michitaka Ohtaki, Effects of Ga Substitution for Co-site on the High-temperature Thermoelectric Properties and Microstructure of the Cobalt-based Oxides, The 29th International Conference on Thermoelectrics, 2010.06.
147. Michitaka Ohtaki, Tomohiro Masuda, Shinobu Teraoka, Kiyoshi Yamamoto, Unconventional Reduction of Lattice Thermal Conductivity in Metal Oxides, The 29th International Conference on Thermoelectrics, 2010.06.
148. Michitaka Ohtaki, Oxide Thermoelectric Materials for Power Generation Recuperating Waste Heat Energy, The 5th International Symposium on Novel Carbon Resource Sciences, 2010.04.
149. Michitaka Ohtaki, Thermoelectric properties and bulk nanocomposite structure of co-doped ZnO, Wilhelm and Else Heraeus Seminar on "Nanostructured Thermoelectric Materials", 2010.02.
150. Michitaka Ohtaki, Shinobu Teraoka, Kiyoshi Yamamoto, Tohru Sugahara, Selective Suppression of Lattice Thermal Conductivity in Oxide Thermoelectric Materials for Higher ZT, The 34th International Conference and Exposition on Advanced Ceramics and Composites, 2010.01.
151. 大瀧倫卓, 山本清司, 共ドープした酸化亜鉛系熱電変換材料の輸送特性と熱電性能, 第48回セラミックス基礎科学討論会, 2010.01.
152. 菅原徹, 大瀧倫卓, 熱電材料におけるペロブスカイト型酸化物の結晶構造と熱物性, 第48回セラミックス基礎科学討論会, 2010.01.
153. 大瀧倫卓, 中高温廃熱利用発電を目的とした金属酸化物熱電変換材料の開発, 第87回産学交流サロン「魅力的な物性を持つマテリアル:金属酸化物~機能性 金属酸化物の応用と今後の展望について~」, 2009.12.
154. 森雅俊, 大瀧倫卓, 界面活性剤ミセルを鋳型としたナノ層状構造タンタル酸Naの自己集積合成と光触媒特性, 2009年日本化学会西日本大会, 2009.11.
155. M. Ohtaki, Oxide Ceramic Materials for Mid-to-High Temperature Thermoelectric Power Generation, Materials Science and Technology 2009 Conference & Exhibition, 2009.10.
156. M. Ohtaki, T. Masuda, S. Teraoka, K. Yamamoto, Unconventional Reduction of Thermal Conductivity in Thermoelectric Oxides, The IUMRS International Conference on Advanced Materials 2009, 2009.09.
157. 大瀧倫卓, 池田寛, 伊勢田幸範, 分子集合体鋳型を用いた電解酸化析出法による酸化物ナノ超格子薄膜の自己組織合成, 日本セラミックス協会第22回秋季シンポジウム, 2009.09.
158. 寺岡忍, 大瀧倫卓, ペロブスカイト型酸化物の構造相転移に伴う熱伝導率の特異的低減, 日本セラミックス協会第22回秋季シンポジウム, 2009.09.
159. 菅原徹, 大瀧倫卓, ペロブスカイト型酸化物熱電材料における熱伝導率の低減と置換サイト依存性, 日本セラミックス協会第22回秋季シンポジウム, 2009.09.
160. 大瀧倫卓, 酸化物熱電変換材料における熱伝導率低減と材料開発戦略, 日本セラミックス協会第22回秋季シンポジウム, 2009.09.
161. 菅原徹, 大瀧倫卓, Aサイト置換したダブルペロブスカイト型酸化物Sr2-xBaxFeMoO6の結晶構造と高温熱電特性, 応用物理学会2009年秋季講演会, 2009.09.
162. M. Ohtaki, K. Yamamoto, Co-Doping of ZnO with Al and Ga for Efficient Thermal Conductivity Reduction, European Congress on Advanced Materials and Processes, 2009.09.
163. 山本五郎, 大瀧倫卓, ナノ多孔質化AlドープZnOの合成プロセスにおける空孔形成材料の分散度と熱電特性, 第6回日本熱電学会学術講演会, 2009.08.
164. 山本五郎, 大瀧倫卓, ナノ多孔質化AlドープZnOの合成プロセスにおける空孔形成材料の分散度と熱電特性, 第6回日本熱電学会学術講演会, 2009.08.
165. 山本清司, 大瀧倫卓, AlとGaを共ドープしたZnO系酸化物の微細構造と熱電特性, 第6回日本熱電学会学術講演会, 2009.08.
166. 菅原徹, 大瀧倫卓, Sr2-xBaxFeMoO6(0.0≦x≦2.0)の結晶構造と高温熱電特性, 第6回日本熱電学会学術講演会, 2009.08.
167. M. Ohtaki, K. Yamamoto, Lattice Thermal Conductivity and Thermoelectric Properties of Al/Ga co-doped ZnO, The 28th International Conference on Thermoelectrics (ICT-2009), 2009.07.
168. M. Ohtaki, T. Sugahara, Thermoelectric Properties of Double Perovskite-type Oxides: Role of A- and B-site Cations in the Perovskite Structure on the Thermal Conductivity, Thermopower Symposium CH-2009 Novel Thermoelectric Materials, Devices and Applications, 2009.07.
169. M. Ohtaki and S. Teraoka, Anomalous Reduction in the Thermal Conductivity of Peroskite-type Oxide with Structural Phase Transition, CRISMAT Workshop on "Relationship between (Nano)structure and Thermoelectric Properties", 2009.07.
170. 山本五郎, 大瀧倫卓, ポリマー微粒子によるZnO系酸化物のナノ多孔質化と熱電変換特性, 第46回化学関連支部合同九州大会, 2009.07.
171. 山本清司, 大瀧倫卓, AlとGaを共ドープしたZnO系酸化物の熱伝導率と熱電特性, 第46回化学関連支部合同九州大会, 2009.07.
172. 森雅俊, 大瀧倫卓, 二分子膜ミセルを鋳型としたナノ層状NaTaO3の合成と光触媒活性, 第46回化学関連支部合同九州大会, 2009.07.
173. 寺岡忍, 大瀧倫卓, ダブルペロブスカイト型酸化物における温度誘起構造相転移と増強フォノン散乱, 第46回化学関連支部合同九州大会, 2009.07.
174. 菅原徹, 大瀧倫卓, ペロブスカイト型酸化物における熱伝導率のA, B サイト置換依存性, 2009年春季 第56回応用物理学関係連合講演会, 2009.03.
175. 森雅俊, 大瀧倫卓, 分子集合体鋳型を用いたナノ層状構造酸化物の合成と光触媒活性, 日本化学会第89春季年会, 2009.03.
176. 徳留弘優, 大瀧倫卓, 希土類金属とアルミニウムを共ドープしたZnOの熱電特性, 日本セラミックス協会2009年年会, 2009.03.
177. 菅原徹, 大瀧倫卓, 相馬岳, ダブルペロブスカイト型酸化物 Sr2-xBaxFeMoO6 の結晶構造と熱電特性, 日本セラミックス協会2009年年会, 2009.03.
178. 大瀧倫卓, 未利用熱エネルギー回収のための酸化物熱電変換材料の開発, 平成20年度日本伝熱学会九州支部講演会, 2009.03.
179. T. Sugahara, M. Ohtaki, T. Souma, Structure and Thermoelectric Properties of Ba- and K-doped Sr2FeMoO6 Double-perovskite Oxides, The 33rd International Conference and Exposition on Advanced Ceramics and Composites, 2009.01.
180. M. Ohtaki, K. Araki, K. Yamamoto, Binary Doping of ZnO for High ZT n-type Oxide Thermoelectric Materials, The 33rd International Conference and Exposition on Advanced Ceramics and Composites, 2009.01.
181. M. Ohtaki, K. Araki, Thermal and Thermoelectric Properties Al-doped ZnO Ceramics with Highly Dispersed Nanovoid Structures, IUMRS-International Conference in Asia 2008, 2008.12.
182. M. Ohtaki, K. Araki, K. Yamamoto, Transport Properties and Thermoelectric Performance of Binary-doped ZnO Ceramics, IUMRS-International Conference in Asia 2008, 2008.12.
183. 大瀧倫卓, バルクナノコンポジット構造を有する酸化物熱電材料の合成と熱電性能, 粉体粉末冶金協会平成20年度秋季大会(第102回講演大会), 2008.11.
184. M. Ohtaki, R. Hayashi, M. Mori, Self-Assembly Synthesis and Electromagnetic Peculiarities of 2-D Transition Metal Oxide Superlattices with Molecular Assembly Template, PRiME 2008 Joint International Meeting: 214th Meeting of ECS and 2008 Fall Meeting of The Electrochemical Society of Japan, 2008.10.
185. 菅原徹, 大瀧倫卓, 相馬岳, 部分元素置換したダブルペロブスカイト型酸化物Sr2FeMoO6の熱電特性, 日本セラミックス協会第21回秋季シンポジウム, 2008.09.
186. 大瀧倫卓, 荒木和彦, 山本清司, 共ドープしたZnO系セラミックスの熱電特性, 日本セラミックス協会第21回秋季シンポジウム, 2008.09.
187. M. Ohtaki, H. Ikeda, Molecular Assembly Templated Electrochemical Synthesis of Oxide Nano-Superlattice Thin Films and Their Electronic Properties, The 59th Annual Meeting of the International Society of Electrochemistry, 2008.09.
188. 大西恭平, 大瀧倫卓, セラミックハニカム中で焼結した酸化物熱電モジュールの試作, 第5回日本熱電学会学術講演会, 2008.08.
189. 菅原徹, 大瀧倫卓, 相馬岳, 緻密焼結したMn系ダブルペロブスカイト酸化物の熱電特性, 第5回日本熱電学会学術講演会, 2008.08.
190. 山本清司, 荒木和彦, 大瀧倫卓, Gaを共ドープしたZnO系酸化物の熱電特性, 第5回日本熱電学会学術講演会, 2008.08.
191. M. Ohtaki, K. Araki, High Thermoelectric Performance of Dually Doped ZnO Ceramics, The 27th International Conference on Thermoelectrics, 2008.08.
192. 山本清司, 大瀧倫卓, SrTiO3系酸化物の微細構造と熱電特性, 第45回化学関連支部合同九州大会, 2008.07.
193. 森雅俊, 大瀧倫卓, 自己組織化した二次元量子構造酸化物半導体の合成と物性, 第45回化学関連支部合同九州大会, 2008.07.
194. 池田寛, 大瀧倫卓, 分子鋳型を用いた電解酸化法による酸化物ナノ超格子の合成と物性, 第45回化学関連支部合同九州大会, 2008.07.
195. 菅原徹, 大瀧倫卓, 部分元素置換したダブルペロブスカイト型酸化物の構造と熱電特性, 第45回化学関連支部合同九州大会, 2008.07.
196. M. Ohtaki, K. Araki, Transport Properties and Thermoelectric Performance of Oxide Ceramics with Nanovoid Structure, 2nd International Congress on Ceramics, 2008.07.
197. M. Ohtaki, Recent Progress in Oxide Thermoelectric Materials - electron correlation, quantum wells, and bulk nanocomposites -, Empa Seminar, 2008.06.
198. M. Ohtaki, Thermoelectric Properties of ZnO-based Oxide with Nanocomposite Structure, 2nd Workshop on Anisotropic Science and Technology of Materials and Devices (ASTMD-2), 2008.06.
199. 池田寛, 大瀧倫卓, 分子集合体鋳型を用いた金属酸化物ナノ超格子薄膜の電解酸化合成, ナノ学会第6回大会, 2008.05.
200. 大瀧倫卓, 林遼, 層状酸化鉄ナノ超格子の自己組織合成と磁気特性, ナノ学会第6回大会, 2008.05.
201. 菅原徹, 大瀧倫卓, 緻密焼結したダブルペロブスカイト型酸化物 Sr2-xBaxFeMoO6 の熱電特性, 日本セラミックス協会2008年年会, 2008.03.
202. M. Ohtaki, Nano-scale Structure Engineering in Oxide Thermoelectric Materials for Power Generation Applications, The 32nd International Conference and Exposition on Advanced Ceramics and Composites, 2008.01.
203. M. Ohtaki, K. Araki, Thermal Conductivity and Thermoelectric Performance of Al-doped ZnO with Nanovoid Structure, The 10th Eurasia Conference on Chemical Sciences (EuAsC2S-10), 2008.01.
204. T. Souma, D. Isobe, M. Ohtaki, Synthesis and Rietveld Analysis for F-doped NaCo2O4 Thermoelectric Materials, 第18回日本MRS学術シンポジウム, 2007.12.
205. M. Ohtaki, H. Ikeda, R. Hayashi, Self-Assembly Synthesis and Electromagnetic Properties of 2D Nanosized Metal Oxides with Superlattice-like Structure, 第18回日本MRS学術シンポジウム, 2007.12.
206. T. Sugahara, M. Ohtaki, T. Souma, Thermoelectric Properties of Double-Perovskite Oxide A2B'B""O6 with A-Site Substitution, The 9th Cross Straits Symposium on Materials, Energy and Environmental Sciences (CSS9), 2007.11.
207. T. Masuda, M. Ohtaki, Suppression of Thermal Conductivity In Metal Oxides Due to Order-Disorder Transition of Oxide Ion Sublattice, The 9th Cross Straits Symposium on Materials, Energy and Environmental Sciences (CSS9), 2007.11.
208. H. Ikeda, M. Ohtaki, Molecular Templating Electrochemical Synthesis of Nano-Superlattice Thin Films of Layered Oxides and Their Electromagnetic Properties, The 9th Cross Straits Symposium on Materials, Energy and Environmental Sciences (CSS9), 2007.11.
209. K. Ohnishi, M. Ohtaki, Development of Oxide Thermoelectric Modules with a High Density Packing by Using Ceramic Honeycomb, The 9th Cross Straits Symposium on Materials, Energy and Environmental Sciences (CSS9), 2007.11.
210. M. Ohtaki, K. Araki, Thermoelectric Performance of Oxide Ceramics with Nanovoid Structure, 7th Pacific Rim Conference on Ceramic and Glass Technology (PacRim7), 2007.11.
211. 池田寛, 大瀧倫卓, 分子鋳型電解析出法によるMn酸化物ナノ超格子薄膜の自己組織合成と物性, 2007年電気化学秋季大会, 2007.09.
212. N. V. Nong, M. Ohtaki, Effect of Rare-earth Substitution for Ca on High-temperature Thermoelectric Properties and Microstructure of Ca3Co4O9, 日本セラミックス協会第20回秋季シンポジウム, 2007.09.
213. 大瀧倫卓, 池田寛, 林遼, 自己組織合成で得られる遷移金属酸化物ナノ超格子の微細構造と物性, 日本セラミックス協会第20回秋季シンポジウム, 2007.09.
214. M. Ohtaki, R. Hayashi, Structure and Magnetic Properties of Iron Oxide Self-assembly Superlattice Synthesized by Hydrothermal Treatment of Surfactant-directed Lamellar Mesophase, Second International Symposium Advanced Micro- and Mesoporous Materials (micro2007), 2007.09.
215. 大西恭平, 大瀧倫卓, セラミックハニカムを利用した酸化物熱電モジュールの高密度実装プロセスの開発, 第44回化学関連支部合同九州大会, 2007.07.
216. 池田寛, 大瀧倫卓, 分子鋳型電解析出法による層状酸化物薄膜の合成, 第44回化学関連支部合同九州大会, 2007.07.
217. 益田智博, 大瀧倫卓, ペロブスカイト型酸化物における酸素イオン副格子の秩序-無秩序転移とフォノン散乱, 第44回化学関連支部合同九州大会, 2007.07.
218. 上中達也, 大瀧倫卓, RFe2O4系n型層状酸化物の熱電性能, 第44回化学関連支部合同九州大会, 2007.07.
219. 荒木和彦, 大瀧倫卓, 高分散ナノボイド構造を有するZnO型酸化物のフォノン散乱と熱電特性, 第44回化学関連支部合同九州大会, 2007.07.
220. 菅原徹, 大瀧倫卓, Aサイト置換したダブルペロブスカイト型酸化物の熱電特性, 第44回化学関連支部合同九州大会, 2007.07.
221. M. Ohtaki, R. Hayashi, Self-Assembly Synthesis and Electromagnetic Properties of 2D Transition Metal Oxides Interleaved by Highly Regulated Nanospace, Japan-USA Joint Symposium on Chemistry of Coordination Space (JUJS-CCS 2007), 2007.06.
222. M. Ohtaki, R. Hayashi, K. Araki, Thermoelectric Properties of Sintered ZnO Incorporating Nanovid Structure: Influence of the Size and Number Density of Nanovoids, The 26th International Conference on Thermoelectrics (ICT-2007), 2007.06.
223. T. Souma, M. Ohtaki, K. Ohnishi, M. Shigeno , Y. Ohba, N. Nakamura, T. Shimozaki, Power Generation Characteristics of Oxide Thermoelectric Modules Incorporating Nanostructured ZnO Sintered Materials, The 26th International Conference on Thermoelectrics (ICT-2007), 2007.06.
224. N. V. Nong, M. Ohtaki, High-temperature Thermoelectric Properties of Ca3Co4O9 with Late Rare-Earth Metals Substitutions, 日本セラミックス協会2007年年会, 2007.03.
225. 益田智博, 大瀧倫卓, ペロブスカイト型酸化物における酸素イオン副格子の構造相転移とフォノン散乱, 日本セラミックス協会2007年年会, 2007.03.
226. 荒木和彦, 大瀧倫卓, 高分散ナノボイド構造を有するZnO系酸化物の構造と熱電特性, 日本セラミックス協会2007年年会, 2007.03.
227. M. Ohtaki, R. Hayashi, K. Araki, High Thermoelectric Performance of Al-doped ZnO Induced by Nanovoid Structure, The 31st International Cocoa Beach Conference on Advanced Ceramics and Composites, 2007.01.
228. M. Ohtaki, K. Araki, R. Hayashi, Thermoelectric Performance of ZnO-based Oxide Enhanced by Nanovoid Structure, The 8th International Symposium on Eco-Materials Processing and Design (ISEPD 2007), 2007.01.
229. 相馬岳, 大瀧倫卓, 重野雅之, 大庭康弘, 中村憲和, 下崎敏唯, Jointing Technique and Power Generation Characteristics of p-NaCo2O4/n-ZnO Oxide Thermoelectric Modules, 第17回日本MRS学術シンポジウム, 2006.12.
230. M. Ohtaki, R. Hayashi, Self-Assembly Synthesis of Iron Oxide Superlattice Showing Anomalous Spin-phase Transitions Driven by Highly Regulated Interlayer Nanospace, The Second International Symposium on Chemistry of Coordination Space (ISCCS2006), 2006.12.
231. 西田達朗, 大瀧倫卓, Synthesis and Photocatalytic Properties of Nanosized Layered-TiO2 Intercalated with Linear Alcohols, 第17回日本MRS学術シンポジウム, 2006.12.
232. 林遼, 大瀧倫卓, 自己集積した酸化鉄ナノ超格子の構造観察と磁気特性, 2006年日本化学会西日本大会, 2006.11.
233. 大瀧倫卓, 林亮介, ナノボイド構造ZnOにおける格子欠陥生成と熱電性能, 2006年日本化学会西日本大会, 2006.11.
234. N. V. Nong, M, Ohtaki, Thermoelectric Properties of Rare Earth-doped Ca-Co-O Oxides, 日本セラミックス協会第19回秋季シンポジウム, 2006.09.
235. 大瀧倫卓, 林亮介, ナノ粒子分散プロセスによりナノボイド構造を導入したAlドープZnO系酸化物の熱電性能, 日本セラミックス協会第19回秋季シンポジウム, 2006.09.
236. M. Ohtaki, Y. Uchino, R. Hayashi, Synthesis and Magnetic Properties of Lamellar Iron Oxide-Surfactant Nanocomposite with Self-assembly Superlattice Structure, The 5th International Conference on Inorganic Materials, 2006.09.
237. M. Ohtaki, R. Hayashi, Nanostructured ZnO-based Oxide: A Promising Thermoelectric Material For High-Temperature Waste Heat Recovery, The 9th Eurasia Conference on Chemical Science (EuAsC2S-9), 2006.09.
238. 大瀧倫卓, 林亮介, 高分散ナノボイド構造を導入したAlドープZnOの熱電特性, 第3回日本熱電学会学術講演会, 2006.08.
239. T. Souma, M. Ohtaki, M. Shigeno, Y. Ohba, N. Nakamura, T. Shimozaki, Fabrication and power generation characteristics of p-NaCo2O4/n-ZnO oxide thermoelectric modules, The 25th International Conference on Thermoelectrics (ICT-2006), 2006.08.
240. T. Souma, M. Ohtaki, Optimization on preparation conditions in Sb self-flux method for CoTiSb and NiTiSb Half-Heusler compounds, The 25th International Conference on Thermoelectrics (ICT-2006), 2006.08.
241. T. Souma, M. Ohtaki, Synthesis and Rietveld analysis for CoSb3 compounds prepared by Sb self-flux method (II), The 25th International Conference on Thermoelectrics (ICT-2006), 2006.08.
242. T. Souma, M. Ohtaki, Relation between Zn content and thermoelectric properties of Zn4+xSb3 (-0.12≦x≦0.12), The 25th International Conference on Thermoelectrics (ICT-2006), 2006.08.
243. N. V. Nong, M. Ohtaki, Thermoelectric properties and local electronic structure of rare earth-doped Ca3Co2O6, The 25th International Conference on Thermoelectrics (ICT-2006), 2006.08.
244. M. Ohtaki, R. Hayashi, Enhanced Thermoelectric Performance of Nanostructured ZnO: A possibility of selective phonon scattering and carrier energy filtering by nanovoid structure, The 25th International Conference on Thermoelectrics (ICT-2006), 2006.08.
245. M. Ohtaki, H. Hirobe, R. Hayashi, Thermoelectric Performance and Transport Properties of Oxide Materials with Nanosized Defect Structures, 11th International Conferences on Modern Materials and Technologies (CIMTEC 2006), 2006.06.
特許出願・取得
特許出願件数  2件
特許登録件数  3件
学会活動
所属学会名
日本化学会
日本セラミックス協会
日本熱電学会
電気化学会
The American Ceramic Society
International Thermoelectric Society
学協会役員等への就任
2023.04~2025.03, 日本セラミックス協会九州支部, 会長.
2022.07~2024.06, 日本熱電学会, 会長.
2022.03~2024.03, 電気化学会, 代議員(九州支部推薦).
2021.04~2023.03, 日本セラミックス協会九州支部, 副支部長.
2018.07~2022.06, 日本熱電学会, 副会長.
2004.04, 日本熱電学会, 理事.
2014.04, 電気化学会九州支部, 幹事常議員.
2014.07~2018.06, 日本熱電学会, 運営委員.
2008.04~2022.04, 日本セラミックス協会九州支部, 幹事常議員.
2008.04~2014.03, 日本セラミックス協会, 運営委員.
2017.04~2025.03, 日本セラミックス協会 分野横断型研究体「革新的熱利用・熱制御材料研究体」, 代表世話人.
2000.04, 日本セラミックス協会, 生体関連材料部会 役員.
2012.07~2014.06, 日本熱電学会, 運営委員.
2002.02~2003.02, 日本化学会, 九州支部庶務幹事.
2000.04~2001.03, 日本化学会, 九州支部代議員.
2002.04~2003.03, 日本化学会, 九州支部代議員.
1999.04~2001.03, 電気化学会, 九州支部庶務幹事.
学会大会・会議・シンポジウム等における役割
2023.01.22~2023.01.27, The 47th International Conference and Expo on Advanced Ceramics and Composites (ICACC2023), Symposium Lead Organizer.
2022.09.14~2022.09.16, 日本セラミックス協会第35回秋季シンポジウム, 特定セッション25「熱エネルギーの利用と制御における材料革新Ⅲ〜熱エネルギー変換・熱制御・蓄熱・超伝熱・超断熱材料の新展開〜」代表オーガナイザ.
2022.01.23~2022.01.28, The 46th International Conference and Expo on Advanced Ceramics and Composites (ICACC2022), Symposium Lead Organizer.
2021.12.12~2021.12.17, The 14th Pacific Rim Conference of Ceramic Societies (PacRim14), Symposium Lead Organizer.
2021.09.01~2021.09.03, 日本セラミックス協会第34回秋季シンポジウム, 特定セッション25「熱エネルギーの利用と制御における材料革新Ⅱ〜熱エネルギー変換・熱制御・蓄熱・超伝熱・超断熱材料の新展開〜」代表オーガナイザ.
2021.01.31~2021.02.04, The 45th International Conference and Expo on Advanced Ceramics and Composites (ICACC2021), Symposium Lead Organizer.
2020.09.02~2020.09.04, 日本セラミックス協会第33回秋季シンポジウム, 特定セッション10「エネルギー変換・貯蔵・輸送セラミックス材料の基礎と応用」セッション・オーガナイザ.
2020.01.26~2020.01.31, The 44th International Conference and Expo on Advanced Ceramics and Composites (ICACC2020), Symposium Organizer.
2019.10.27~2019.10.31, The 13th Pacific Rim Conference of Ceramic Societies (PacRim13), Symposium Lead Organizer.
2018.09.05~2018.09.07, 日本セラミックス協会第31回秋季シンポジウム, 特定セッション02「熱エネルギーの利用と制御における材料革新〜熱エネルギー変換・伝熱・遮熱・蓄熱・熱制御材料の新展開〜」代表オーガナイザ.
2018.08.20~2018.08.23, Materials Challenges in Alternative and Renewable Energy (MCARE) 2018, Conference Co-organizer.
2018.07.22~2018.07.27, The 12th International Conference on Ceramic Materials and Components for Energy and Environmental Applications (CMCEE 2018), Symposium Lead Organizer.
2017.11.22~2017.11.24, The 34th International Japan-Korea Seminar on Ceramics, 組織委員.
2017.11.14~2017.11.16, 第58回電池討論会, 実行委員.
2017.09.13~2017.09.13, 第14回日本熱電学会学術講演会(TSJ2017)公募シンポジウム「固体材料における熱伝導制御の学術フロンティア」, 代表オーガナイザ.
2017.09.10~2017.09.11, 2017年電気化学秋季大会, 実行委員.
2017.08.27~2017.09.01, The 15th IUMRS International Conference on Advanced Materials (IUMRS-ICA2017), Symposium Organizer.
2017.05.21~2017.05.26, The 12th Pacific Rim Conference on Ceramic and Glass Technology (PacRim12), Symposium Organizer.
2017.02.17~2017.02.20, The 18th International Symposium on Eco-materials Processing and Design (ISEPD2017), 実行委員.
2016.08.26~2016.08.27, 第6回九州若手セラミックフォーラム(KYCF-6) &第46回窯業基礎九州懇話会, 実行委員長.
2016.01.19~2016.01.20, International Conference on Organic and Hybrid Thermoelectrics (ICOT2016), 組織委員.
2015.09.07~2015.09.08, 日本熱電学会第12回学術講演会(TSJ2015), 実行委員長.
2015.06.14~2015.06.19, The 11th International Conference on Ceramic Materials and Components for Energy and Environmental Applications (CMCEE-11), Symposium Lead Organizer.
2015.02.05~2015.02.06, The First Joint Symposium of Kyushu University and Yonsei University on Materials Science and Chemical Engineering (SKY-1) , 座長(Chairmanship).
2014.12.14~2014.12.18, The 13th Eurasia Conference on Chemical Sciences (EuAsC2S-13), 座長(Chairmanship).
2014.11.17~2014.11.19, The Second International Workshop on Nano Materials for Energy Conversion (NMEC-2), 座長(Chairmanship).
2014.08.24~2014.08.29, IUMRS International Conference in Asia (IUMRS-ICA) 2014, 座長(Chairmanship).
2015.02.05~2015.02.06, The First Joint Symposium of Kyushu University and Yonsei University on Materials Science and Chemical Engineering (SKY-1) , Organizer.
2014.12.14~2014.12.18, The 13th Eurasia Conference on Chemical Sciences (EuAsC2S-13), International Advisory Board.
2014.09.09~2014.09.11, 日本セラミックス協会第27回秋季シンポジウム, 実行委員.
2014.08.24~2014.08.29, IUMRS-ICA2014, セッション・オーガナイザ.
2008.12.09~2008.12.14, IUMRS-ICA2008, セッション・オーガナイザ.
2008.09.17~2008.09.19, 日本セラミックス協会第21回秋季シンポジウム, 実行委員.
2008.05.07~2008.05.09, ナノ学会第6回大会, 実行委員.
2007.11~2007.11, 第48回電池討論会, 実行委員.
2005.12~2005.12, 第16回日本MRS学術シンポジウム, セッションオーガナイザ.
2004.12~2004.12, 第15回日本MRS学術シンポジウム, セッションオーガナイザ.
2003.10~2003.10, IUMRS-ICAM2003 Symposium C-6: "Advanced Thermoelectric Materials for Environment-Friendly Energy Systems", Correspondence Chairman.
2002.11~2002.11, 第43回電池討論会, 実行委員.
学会誌・雑誌・著書の編集への参加状況
2010.04~2013.03, 日本セラミックス協会学術論文誌(Journal of Ceramic Society of Japan), 国内, 編集委員.
2004.04~2008.03, 日本熱電学会学術論文誌(Journal of Thermoelectrics Society of Japan), 国内, 編集委員.
2000.04~2003.03, 日本セラミックス協会学術論文誌(Journal of Ceramic Society of Japan), 国内, 編集委員.
学術論文等の審査
年度 外国語雑誌査読論文数 日本語雑誌査読論文数 国際会議録査読論文数 国内会議録査読論文数 合計
2014年度
2013年度
2012年度
2011年度
2010年度 15  15 
2009年度 12  15 
2008年度
2007年度 10  15 
2006年度 15  19 
2005年度
2004年度
2003年度 40  49 
その他の研究活動
外国人研究者等の受入れ状況
2016.06~2016.08, 1ヶ月以上, Mahidol University, Thailand, 外国政府・外国研究機関・国際機関.
2010.11~2013.03, 1ヶ月以上, 九州大学, Vietnam, 文部科学省.
2006.10~2008.03, 1ヶ月以上, 九州大学, Vietnam, 科学技術振興事業団.
受賞
2023 Global Star Award, The American Ceramic Society, 2023.01.
日本セラミックス協会 第74回学術賞, 公益社団法人 日本セラミックス協会, 2019.11.
日本熱電学会学術賞, 一般社団法人日本熱電学会, 2018.09.
研究資金
科学研究費補助金の採択状況(文部科学省、日本学術振興会)
2023年度~2025年度, 挑戦的研究(萌芽), 代表, 共ドープによる固溶元素の安定化効果に基づく熱力学的に安定なバルクp型ZnOの創製.
2022年度~2024年度, 基盤研究(B), 代表, 導電性ナノ粒子によりフォノン散乱と導電性を同時に増強した酸化物熱電材料の開発.
2019年度~2021年度, 基盤研究(B), 代表, 酸化物/窒化物へテロ界面を持つバルクナノコンポジット熱電変換材料の開発.
2016年度~2018年度, 挑戦的萌芽研究, 代表, 構造-電子相転移の併発による動的サーマルインシュレーション材料の開発.
2014年度~2016年度, 基盤研究(B), 代表, バルクナノへテロ構造を有する酸化物熱電変換材料の開発.
2013年度~2015年度, 挑戦的萌芽研究, 代表, 結晶構造中にかご状空間を有する「ラトリング」酸化物熱電材料の開発.
2008年度~2009年度, 萌芽研究, 代表, ナノサイズ領域の独立閉気孔構造によるフォノン熱伝導の特異的低減.
2008年度~2009年度, 萌芽研究, 代表, ナノサイズ領域の独立閉気孔構造によるフォノン熱伝導の特異的低減.
2006年度~2008年度, 基盤研究(B), 代表, 金属酸化物の熱電物性における酸素イオン副格子の構造とダイナミクス.
2004年度~2005年度, 萌芽研究, 代表, 精緻な階層的ナノ構造を持つ酸化物半導体超構造の合成と物性.
2001年度~2003年度, 基盤研究(C), 代表, 導電性酸化物における高エントロピー伝導と熱電変換材料への応用.
1999年度~2000年度, 奨励研究(A), 代表, 二分子膜−酸化物層状複合体の低温結晶化による二次元量子閉じ込め構造半導体の創製.
1997年度~1998年度, 奨励研究(A), 代表, 分子集合体テンプレートの可溶化機能を利用した量子サイズ酸化物複合体の創製.
1997年度~1997年度, 重点領域研究, 代表, 2相から成る高速酸素イオン導電性固体電解質の合成と評価.
1996年度~1996年度, 奨励研究(A), 代表, 分子集合体を鋳型とした量子ヘテロ構造半導体の合成.
1995年度~1995年度, 奨励研究(A), 代表, 金属酸化物半導体へのアニオンドーピング.
1994年度~1994年度, 奨励研究(A), 代表, 常温液相プロセスを利用した金属および半導体超微粒子の精密合成.
1993年度~1993年度, 奨励研究(A), 代表, 無機超微粒子と有機分子を複合分散したミクロ多孔質半導体材料の合成と光機能化.
競争的資金(受託研究を含む)の採択状況
2020年度~2022年度, 戦略的創造研究推進事業 (文部科学省), 連携, 微小エネルギーを利用した革新的な環境発電技術の創出
「低熱伝導率材料を用いた熱電モジュールの開発」.
2017年度~2017年度, NEDO未利用熱エネルギーの革新的活用技術研究開発/熱電変換材料の技術シーズ発掘小規模研究開発, 分担, 溶射法を利用した熱電変換モジュールの研究開発.
2011年度~2014年度, Danish Council for Independent Research, Technology and Production, 分担, OTE-POWER – Oxide thermoelectrics for effective power generation from waste heat.
2009年度~2011年度, 文部科学省 知的創造による地域産学官連携強化プログラム「知的クラスター創成事業」, 分担, 超高効率化を実現するナノ構造熱電発電モジュールの開発.
2008年度~2012年度, 研究拠点形成費補助金(グローバルCOE) (文部科学省), 分担, 新炭素資源学.
2008年度~2008年度, 科学技術振興機構 地域イノベーション創出総合支援事業 重点地域研究開発推進プログラム「シーズ発掘試験」, 代表, 多元ドープによるバルクナノコンポジット構造ZnO系酸化物熱電材料の開発.
2002年度~2007年度, 科学技術振興機構 戦略的創造研究推進事業(CREST), 分担, ナノブロックインテグレーションによる層状酸化物熱電材料の創製.
2006年度~2006年度, 科学技術振興機構 地域イノベーション創出総合支援事業 重点地域研究開発推進プログラム「シーズ発掘試験」, 代表, セラミックハニカムを用いた高密度実装酸化物熱電発電モジュールの開発.
2002年度~2005年度, 科学技術振興機構 重点地域研究開発促進事業, 代表, 500℃級排熱回収用熱電発電素子の開発.
共同研究、受託研究(競争的資金を除く)の受入状況
2018.04~2018.11, 代表, 熱制御材料の開発.
2017.04~2018.03, 代表, 熱制御材料の開発.
2016.04~2017.03, 代表, 熱制御材料の開発.
2015.04~2016.03, 代表, 熱制御材料の開発.
2011.04~2012.03, 代表, 高効率酸化物熱電変換材料に関する研究.
2010.05~2011.03, 代表, 高効率酸化物熱電変換材料に関する研究.
2010.01~2010.09, 代表, 高性能熱電変換材料の開発.
寄附金の受入状況
2018年度, 公益財団法人大倉和親記念財団, 公益財団法人大倉和親記念財団 2018年度第49回研究助成金/窒化物シェルを拡散防止層とする超耐熱性ナノコンポジット酸化物熱電変換材料の開発.
2009年度, 昭和電線ケーブルシステム株式会社, 奨学寄付金.
2009年度, TOTO株式会社, 奨学寄付金.
2009年度, 日揮触媒化成株式会社, 奨学寄付金.
2010年度, 日揮触媒化成株式会社, 奨学寄付金.
学内資金・基金等への採択状況
2002年度~2003年度, 九州大学教育研究プログラム・研究拠点形成プロジェクト(P&P)(B-2タイプ), 代表, 階層的ナノ構造の時空間制御による無機ナノフォトニクス材料の創製.
2002年度~2003年度, 九州大学教育研究プログラム・研究拠点形成プロジェクト(P&P)(Cタイプ), 分担, 次世代のソフトエネルギーに関する最先端教育プログラムの構築.
2002年度~2004年度, 九州大学教育研究プログラム・研究拠点形成プロジェクト(P&P)(Aタイプ), 分担, 次世代化学機能デバイスの基盤技術としてのセラミックスウェットプロセッシング −ナノレベルからの構造と機能の制御−.

九大関連コンテンツ

pure2017年10月2日から、「九州大学研究者情報」を補完するデータベースとして、Elsevier社の「Pure」による研究業績の公開を開始しました。