|
Affiliation |
Engineering educational research section Electrical and Electronic System Program |
|
Title |
Associate Professor |
|
Homepage |
|
|
External Link |
|
|
Related SDGs |
|
NAGAOKA Akira
|
|
|
Research Areas 【 display / non-display 】
-
Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Electric and electronic materials
-
Nanotechnology/Materials / Energy chemistry
Education 【 display / non-display 】
-
University of Miyazaki
2011.4 - 2014.3
Country：Japan
-
University of Miyazaki Graduate School, Division of Engineering
2009.4 - 2011.3
Country：Japan
-
University of Miyazaki Faculty of Engineering
2005.4 - 2009.3
Country：Japan
External Career 【 display / non-display 】
-
東京科学大学フロンティア材料科学研究所 共同研究員
2017.4
Country：Japan
-
九州大学応用力学研究所 共同研究員
2017.4
Country：Japan
-
Kyoto University
2017.4 - 2018.10
Country：Japan
-
University of Utah 日本学術振興会海外特別研究員
2015.4 - 2017.3
Country：United States
-
Kyoto University
2014.4 - 2015.3
Country：Japan
Professional Memberships 【 display / non-display 】
-
JSAP: Japan Society of Applied Physics
-
IEEE
-
日本セラミックス協会
-
Professional Group of Multinary Compounds and Solar Cells
-
Thermoelectrics Society of Japan
Papers 【 display / non-display 】
-
Realizing a thermoelectric conversion efficiency of 10% with long-term stability in a kesterite Cu2ZnSn(S1−xSex)4single-leg device Reviewed International coauthorship
Nagaoka A., Miura S., Nomoto K., Chen K., Sato N., Yoshino K., Nishioka K.
Journal of Materials Chemistry A 14 6846 - 6857 2026.1
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Materials Chemistry A
The application of thermoelectric (TE) technology, contributing to carbon neutrality by the recovery of global waste heat, is hindered by low conversion efficiencies and high costs, demonstrating a strong demand for high-performance TE materials with environmentally friendly characteristics. Multinary Cu<inf>2</inf>ZnSnS<inf>4</inf> (CZTS)-based materials have attracted considerable attention for TE power generation owing to their cost-effectiveness and earth-abundant features. However, their dimensionless figure of merit (ZT), which is the critical measure of TE performance, is relatively lower than that of other TE-material-based systems. Herein, we report the discovery of p-type Cu<inf>2</inf>ZnSn(S<inf>1−x</inf>Se<inf>x</inf>)<inf>4</inf> (CZTSSe) single crystals with a record-high ZT of 1.9 at 800 K and high TE conversion efficiency of ∼10% at a temperature difference of 473 K with long-term stability over 1000 h. The exceptional performance originates from a high power factor and intrinsically low thermal conductivity owing to the pseudo-cubic structure, alkali element doping, and short-range lattice distortion. This study demonstrates the potential of CZTS-based TE materials for intermediate-temperature TE harvesting.
DOI： 10.1039/d5ta08640j
-
日焼け止めを用いた紫外線教育の教材開発による理系選択支援 Reviewed
吉野 賢二, 永岡 章
工学教育 73 ( 6 ) 52 - 55 2025.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：公益社団法人 日本工学教育協会
-
宮崎の特色を生かした再生可能エネルギー教育と地域貢献 Reviewed
吉野 賢二, 永岡 章
工学教育 73 ( 5 ) 146 - 149 2025.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：公益社団法人 日本工学教育協会
-
Thermoelectric chalcopyrite-type ZnSnAs2 compound with high power factor for low-grade waste-heat recovery Reviewed International coauthorship
Nakashima K., Miura S., Ienaga H., Nomoto K., Yoshino K., Nishioka K., Nagaoka A.
Journal of Alloys and Compounds 1033 181275-1 - 181275-7 2025.6
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Alloys and Compounds
Chalcopyrite compounds are promising thermoelectric (TE) materials owing to their excellent performance. Adopting a pseudocubic structure is a key strategy to improve the TE performance as it increases the degeneracy at the valence band edge. Herein, the TE properties of a II-IV-V<inf>2</inf> group, p-type ZnSnAs<inf>2</inf> chalcopyrite with a pseudocubic structure are systematically investigated. Polycrystalline, single phase, stoichiometric ZnSnAs<inf>2</inf> was obtained at growth temperatures above 700 ºC. The TE properties of ZnSnAs<inf>2</inf> depended on its intrinsic defect concentration, which was influenced by its Zn/Sn ratios. A high power factor value of 2890 μW/mK<sup>2</sup> was obtained in Zn-poor Zn<inf>0.9</inf>Sn<inf>1.1</inf>As<inf>2</inf> at 373 K. The TE figure of merit for the off-stoichiometric ZnSnAs<inf>2</inf> reached 0.1 at 573 K. Consequently, a maximum TE conversion efficiency of ∼1 % at a temperature gradient of 300 K was demonstrated for a ZnSnAs<inf>2</inf>-based single-leg device. These results can accelerate the development of TE technologies for low-energy harvesting.
-
Enhancing Power Factor in n-type Chalcopyrite CdSnAs₂ Thermoelectrics via Supercooled Solidification Reviewed
Kishida, Shoki; Okamoto, Norihiko; Katsube, Ryoji; Nagaoka, Akira; Sumiyoshi, Isshin; Nishioka, Kensuke; ichitsubo, tetsu; Nose, Yoshitaro
ACS Applied Energy Materials 8 7475 - 7482 2025.5
Language：English Publishing type：Research paper (scientific journal)
Books 【 display / non-display 】
-
熱、排熱利用に向けた 材料・熱変換技術の開発と活用事例
永岡 章（ Role： Contributor , 環境調和型Cu2ZnSnS4 (CZTS)熱電変換材料の開発とデバイス応用）
（株）技術情報協会 2025.5
Language：Japanese Book type：Scholarly book
-
国立大学で工学を学ぼう vol. 2
永岡 章（ Role： Contributor , 身近な温度差を電気に換える「熱電変換」材料）
株式会社フロムページ 2022.1
Language：Japanese Book type：Scholarly book
-
Copper Zinc Tin Sulfide-Based Thin Film Solar Cells
Akira Nagaoka and Kenji Yoshino（ Role： Joint author , Chapter 6 Growth of CZTS single crystals）
Wiley 2015
Responsible for pages：133-148 Language：Japanese Book type：Scholarly book
-
電子機器・部品における故障・発火原因解析と対策技術
永岡章, 吉野賢二（ Role： Joint author）
技術情報協会 2014
Responsible for pages：587-591 Language：Japanese Book type：Scholarly book
MISC 【 display / non-display 】
-
日本熱電学会 2024年受賞者紹介 進歩賞 Invited
永岡 章
日本熱電学会誌 21 ( 1 ) 3 - 4 2024.8
Authorship：Lead author Language：Japanese Publishing type：Internal/External technical report, pre-print, etc. Publisher：日本熱電学会
-
最先端測定技術を用いたII-VI族化合物半導体中の局所構造の解明 Invited
永岡 章
クリーンエネルギー 33 ( 1 ) 51 - 60 2024.1
Authorship：Lead author, Corresponding author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)
-
廃熱を有効活用する環境調和型熱電変換デバイスの開発 Invited
永岡 章
月刊機能材料 ( 3月号 ) 2023.3
Authorship：Lead author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)
-
研究室紹介 宮崎大学工学部 環境・エネルギー工学研究センター Invited
永岡 章
日本熱電学会誌 19 ( 2 ) 82 - 83 2022.12
Authorship：Lead author Language：Japanese Publishing type：Internal/External technical report, pre-print, etc. Publisher：日本熱電学会
-
無次元性能指数ZT=1.6を示す環境調和型Cu2ZnSnS4単結晶 Invited
永岡 章
日本熱電学会誌 18 ( 3 ) 142 2022.4
Authorship：Lead author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal) Publisher：日本熱電学会
Presentations 【 display / non-display 】
-
Thermoelectric conversion efficiency exceeding 10% by alkali doping in kesterite Cu₂ZnSn(S1-xSex)4 single crystals International coauthorship International conference
Akira Nagaoka, Keita Nomoto, Naoki Sato, Kenji Yoshino, and Kensuke Nishioka
42nd International Conference on Thermoelectrics (ICT2026) 2026.5.18
Event date： 2026.5.17 - 2026.5.21
Language：English Presentation type：Poster presentation
-
Thermal energy harvesting from window-integrated photovoltaics for zero-energy buildings International conference
M. Mori, S. Miura, Y. Ota, K. Nishioka, S. Ikeda, A. Nagaoka
42nd International Conference on Thermoelectrics (ICT2026) 2026.5.19
Event date： 2026.5.17 - 2026.5.21
Language：English Presentation type：Poster presentation
-
Effect of Cu doping on thermoelectric properties of chalcopyrite ZnSnAs2 International coauthorship International conference
Hiroki Ienaga, Keita Nomoto, Akira Nagaoka
42nd International Conference on Thermoelectrics (ICT2026) 2026.5.18
Event date： 2026.5.17 - 2026.5.21
Language：English Presentation type：Poster presentation
-
Growth and thermoelectric characterization of Weyl semimetal NbIrTe4 bulk crystals International conference
Haruki Takagi, Hiroki Ienaga, Yusuke Ohshima, Shinichi Kato, Akira Nagaoka
42nd International Conference on Thermoelectrics (ICT2026) 2026.5.18
Event date： 2026.5.17 - 2026.5.21
Language：English Presentation type：Poster presentation
-
新規材料Li-doped MAO を用いたリチウムイオン電池用セパレータの保護膜開発
宇都 大樹, 安井 伸太郎, 永岡 章, 吉野 賢二
第73回応用物理学会春季学術講演会 2026.3.17
Event date： 2026.3.15 - 2026.3.18
Language：Japanese Presentation type：Oral presentation (general)
Awards 【 display / non-display 】
-
Outstanding Poster Award
2025.6 41st International Conference on Thermoelectrics and 7th Asian Conference on Thermoelectrics (ICT/ACT 2025) Thermoelectric Conversion Efficiency of 10% in Kesterite Cu2ZnSn(S1−xSex)4 Single-Leg Device
Akira Nagaoka
Award type：Award from international society, conference, symposium, etc.
-
令和6年度ハイステップ研究者表彰
2025.3 宮崎大学
永岡 章
-
第6回フロンティア太陽電池セミナー優秀賞
2024.12 フロンティア太陽電池セミナー実行委員会 THM法によるGa-doped CdTe単結晶成長
都留 颯人，吉野 賢二，永岡 章，野瀬 嘉太郎，住吉 壱心
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
-
日本熱電学会 2024年進歩賞
2024.9 一般社団法人日本熱電学会 高品質な多元系化合物単結晶成長技術を基盤とした高効率熱電変換材料の開発とデバイス応用
永岡 章
Award type：Award from Japanese society, conference, symposium, etc.
-
Best Poster Prize
2024.9 22nd International Conference on Ternary and Multinary Compounds (ICTMC-22) Impact of structural transition during crystal growth on microstructure and thermoelectric properties in CdSnAs2
S. Kishida, A. Nagaoka and Y. Nose
Award type：Award from international society, conference, symposium, etc.
Grant-in-Aid for Scientific Research 【 display / non-display 】
-
機能性粒界を活用した高効率熱電変換材料の開発
Grant number：23K26603 2024.04 - 2027.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(B)
Authorship：Principal investigator
-
機能性粒界を活用した高効率熱電変換材料の開発
Grant number：23H01910 2023.04 - 2027.03
独立行政法人日本学術振興会 科学研究費補助金 基盤研究(B)
Authorship：Principal investigator
-
IoT用独立型電源のための環境調和型多元系熱電材料の無次元性能指数向上
Grant number：20K15221 2020.04 - 2024.03
独立行政法人日本学術振興会 科学研究費補助金 若手研究
Authorship：Principal investigator
-
高品質ケステライト化合物バルク単結晶を用いた高効率太陽電池デバイスの創製
Grant number：17J07259 2017.04 - 2020.03
科学研究費補助金 特別研究員奨励費
Authorship：Principal investigator
-
高効率太陽電池のためのケステライト化合物単結晶成長と電気特性を中心とした物性評価
Grant number：99999999 2015.04 - 2017.03
科学研究費補助金 特別研究員奨励費
Authorship：Principal investigator
Available Technology 【 display / non-display 】
-
環境調和した高効率熱電変換材料の開発
機能性化合物単結晶成長
ZEB応用に向けたスマートエネルギー利用Related fields where technical consultation is available：バルク単結晶成長に関する内容、熱電変換材料に関する内容、太陽光発電技術に関する内容、ZEB利用に関する内容、機能性材料の物性測定に関する内容
Message：材料開発、特に熱電変換材料と太陽光発電材料に関する評価装置が揃っています。その他気軽にご連絡ください。