Basic Information

Faculty

• 工学部

Academic Degree

• 修士（工学）(京都大学)
• 博士（工学）(京都大学)

Research History

• From Oct. 2018, To Present

  JST PRESTO, researcher
• From Nov. 2016, To Present

  Kyoto Univ., Dept. of Polymer Chemistry, Assistant Professor
• From Sep. 2015, To Sep. 2016

  University of Cambridge, Cavendish Lab., Postdoc
• From Apr. 2013, To Aug. 2015

  Kyoto Univ., Dept. of Polymer Chemistry, Postdoc

Language of Instruction

• English
• Japanese

ID,URL

• ORCID ID

  0000-0002-3074-0208

• J-Global ID

  201601004304033494

• Researcher number

  30794268

researchmap URL

• https://researchmap.jp/ytamai

Research

Research Topics, Overview of the research

• Research Topics

  Exciton and Polaron Dynamics in Polymer Solar Cells

• Overview of the research

  My research interests focuses on photophysics and photochemistry such as formation, diffusion, and decay dynamics of excitons and polarons in organic materials. Those photophysical processes are measured spectroscopically by means of ultrashort pulsed-laser systems. My current research interest focuses on spectroscopic approach to polymer solar cells.

Research Interests

• Ultrafast spectroscopy
• Optoelectronics
• Photophysics/Photochemistry

Research Areas

• Nanotechnology/Materials, Organic functional materials
• Nanotechnology/Materials, Applied materials
• Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Electronic devices and equipment
• Nanotechnology/Materials, Polymer chemistry

Papers

• Molecular Understanding of How the Interfacial Structure Impacts the Open-Circuit Voltage of Highly Crystalline Polymer Solar Cells

  Tomohiro Fukuhara; Koshi Yamazaki; Takuto Hidani; Masahiko Saito; Yasunari Tamai; Itaru Osaka; Hideo Ohkita

  ACS APPLIED MATERIALS & INTERFACES, Jul. 2021, Peer-reviewed

  
• Prolongation of the singlet exciton lifetime of nonfullerene acceptor films by the replacement of the central benzene core with naphthalene

  Tomokazu Umeyama; Kensho Igarashi; Yasunari Tamai; Tatsuho Wada; Taiki Takeyama; Daiki Sasada; Keiichi Ishida; Tomoyuki Koganezawa; Shunsuke Ohtani; Kazuo Tanaka; Hideo Ohkita; Hiroshi Imahori

  Sustainable Energy and Fuels, Apr. 2021

  
• Significantly Sensitized Ternary Blend Polymer Solar Cells with a Very Small Content of the Narrow-Band Gap Third Component That Utilizes Optical Interference

  Masahiko Saito; Yasunari Tamai; Hiroyuki Ichikawa; Hiroyuki Yoshida; Daisuke Yokoyama; Hideo Ohkita; Itaru Osaka

  Macromolecules, 08 Dec. 2020

  
• Sensitizer–host–annihilator ternary-cascaded triplet energy landscape for efficient photon upconversion in the solid state

  Yuji Sakamoto; Yasunari Tamai; Hideo Ohkita

  The Journal of Chemical Physics, 28 Oct. 2020

  
• Delocalization boosts charge separation in organic solar cells

  Yasunari Tamai

  Polymer Journal, 16 Jul. 2020, Peer-reviewed

  
• Two-Dimensional Exciton Diffusion in an HJ-Aggregate of Naphthobisoxadiazole-Based Copolymer Films

  Yasuhiro Murata; Taiki Takeyama; Yuji Sakamoto; Kento Yamaguchi; Yasunari Tamai; Hideo Ohkita

  The Journal of Physical Chemistry C, 18 Jun. 2020, Peer-reviewed

  
• 

  Role of Energy Offset in Nonradiative Voltage Loss in Organic Solar Cells

  Toshiharu Saito; Shin-ichiro Natsuda; Kenta Imakita; Yasunari Tamai; Hideo Ohkita

  Solar RRL, 10 Jun. 2020, Peer-reviewed, Corresponding author

  
• Efficient light-harvesting, energy migration, and charge transfer by nanographene-based nonfullerene small-molecule acceptors exhibiting unusually long excited-state lifetime in the film state

  Tomokazu Umeyama; Kensho Igarashi; Daiki Sasada; Yasunari Tamai; Keiichi Ishida; Tomoyuki Koganezawa; Shunsuke Ohtani; Kazuo Tanaka; Hideo Ohkita; Hiroshi Imahori

  CHEMICAL SCIENCE, Mar. 2020, Peer-reviewed

  
• Impact of Noncovalent Sulfur–Fluorine Interaction Position on Properties, Structures, and Photovoltaic Performance in Naphthobisthiadiazole‐Based Semiconducting Polymers

  Masahiko Saito; Tomohiro Fukuhara; Satoshi Kamimura; Hiroyuki Ichikawa; Hiroyuki Yoshida; Tomoyuki Koganezawa; Yutaka Ie; Yasunari Tamai; Hyung Do Kim; Hideo Ohkita; Itaru Osaka

  Advanced Energy Materials, Feb. 2020, Peer-reviewed

  
• Efficient light-harvesting, energy migration, and charge transfer by nanographene-based nonfullerene small-molecule acceptors exhibiting unusually long excited-state lifetime in the film state

  Tomokazu Umeyama; Kensho Igarashi; Daiki Sasada; Yasunari Tamai; Keiichi Ishida; Tomoyuki Koganezawa; Shunsuke Ohtani; Kazuo Tanaka; Hideo Ohkita; Hiroshi Imahori

  Chemical Science, 2020, Peer-reviewed

  
• Enhanced Hole Transport in Ternary Blend Polymer Solar Cells

  ChemPhysChem, 16 Oct. 2019, Peer-reviewed

  
• Enhanced Hole Transport in Ternary Blend Polymer Solar Cells

  Koshiro Midori; Tomohiro Fukuhara; Yasunari Tamai; Hyung Do Kim; Hideo Ohkita

  CHEMPHYSCHEM, Oct. 2019, Peer-reviewed

  
• Bimolecular recombination and fill factor in crystalline polymer solar cells

  Tomohiro Fukuhara; Yasunari Tamai; Itaru Osaka; Hideo Ohkita

  Japanese Journal of Applied Physics, 01 Aug. 2018, Peer-reviewed

  
• Ultrafast Long-Range Charge Separation in Nonfullerene Organic Solar Cells

  Yasunari Tamai; Yeli Fan; Vincent O. Kim; Kostiantyn Ziabrev; Akshay Rao; Stephen Barlow; Seth R. Marder; Richard H. Friend; S. Matthew Menke

  ACS Nano, 26 Dec. 2017, Peer-reviewed

  
• Exciton and charge dynamics in polymer solar cells

  Yasunari Tamai

  Kobunshi Ronbunshu, 01 Sep. 2017, Peer-reviewed

  
• Exciton and Charge Dynamics in Polymer Solar Cells

  Yasunari Tamai

  KOBUNSHI RONBUNSHU, 2017, Peer-reviewed

  
• Light-Induced Degradation Mechanism in Poly(3-hexylthiophene)/Fullerene Blend Solar Cells

  Advanced Energy Materials, Jun. 2016, Peer-reviewed

  
• Reduced Bimolecular Recombination in Polymer Solar Cells

  Tomohiro Fukuhara; Miki Osaka; Yasunari Tamai; Hideo Ohkita; Hiroaki Benten; Shinzaburo Ito

  JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY, 2016, Peer-reviewed

  
• Transient Absorption Spectroscopy for Polymer Solar Cells

  Hideo Ohkita; Yasunari Tamai; Hiroaki Benten; Shinzaburo Ito

  IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, Jan. 2016, Peer-reviewed

  
• Ultrafast Singlet Fission in a Push-Pull Low-Bandgap Polymer Film

  Yukitomo Kasai; Yasunari Tamai; Hideo Ohkita; Hiroaki Benten; Shinzaburo Ito

  Journal of the American Chemical Society, 30 Dec. 2015, Peer-reviewed

  
• High-efficiency polymer solar cells with small photon energy loss

  Nature Communications, Dec. 2015, Peer-reviewed

  
• Interface Engineering for Ternary Blend Polymer Solar Cells with a Heterostructured Near-IR Dye

  Advanced Materials, Oct. 2015, Peer-reviewed

  
• Exciton Diffusion in Conjugated Polymers: From Fundamental Understanding to Improvement in Photovoltaic Conversion Efficiency

  The Journal of Physical Chemistry Letters, 03 Sep. 2015, Peer-reviewed

  
• Triplet Exciton Dynamics in Fluorene-Amine Copolymer Films

  Yasunari Tamai; Hideo Ohkita; Hiroaki Benten; Shinzaburo Ito

  CHEMISTRY OF MATERIALS, Apr. 2014, Peer-reviewed

  
• One-Dimensional Singlet Exciton Diffusion in Poly(3-hexylthiophene) Crystalline Domains

  The Journal of Physical Chemistry Letters, 16 Jan. 2014, Peer-reviewed

  
• Dye Sensitization in the Visible Region for Low-Bandgap Polymer Solar Cells

  Yanbin Wang; Bo Zheng; Yasunari Tamai; Hideo Ohkita; Hiroaki Benten; Shinzaburo Ito

  JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2014, Peer-reviewed

  
• Charge-carrier generation in organic solar cells using crystalline donor polymers

  Yasunari Tamai; Kazuki Tsuda; Hideo Ohkita; Hiroaki Benten; Shinzaburo Ito

  PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2014, Peer-reviewed

  
• Dynamical Excimer Formation in Rigid Carbazolophane via Charge Transfer State

  Yasunari Tamai; Hideo Ohkita; Jiro Shimada; Hiroaki Benten; Shinzaburo Ito; Sho Yamanaka; Kenji Hisada; Keita Tani; Koji Kubono; Teruo Shinmyozu

  JOURNAL OF PHYSICAL CHEMISTRY A, Aug. 2013, Peer-reviewed

  
• Singlet Fission in Poly(9,9 '-di-n-octylfluorene) Films

  Yasunari Tamai; Hideo Ohkita; Hiroaki Benten; Shinzaburo Ito

  JOURNAL OF PHYSICAL CHEMISTRY C, May 2013, Peer-reviewed

  
• Conformation of single homopolymer chain in microphase-separated block copolymer monolayer studied by scanning near-field optical microscopy

  Yasunari Tamai; Ryojun Sekine; Hiroyuki Aoki; Shinzaburo Ito

  Macromolecules, 23 Jun. 2009, Peer-reviewed

  
• Poly(methacrylate)s Labeled by Perylene Diimide: Synthesis and Applications in Single Chain Detection Studies

  Hiroyuki Aoki; Toshiaki Takahashi; Yasunari Tamai; Ryojun Sekine; Shinji Aoki; Keita Tani; Shinzaburo Ito

  POLYMER JOURNAL, 2009, Peer-reviewed

  

Awards

• 08 Sep. 2011

  The Japanese Photochemistry Association, Outstanding Student Award
• 14 Nov. 2014

  The Japan Society of Applied Physics, 第37回(2014年秋季)応用物理学会講演奨励賞
• 17 Nov. 2016

  第1回フロンティア太陽電池セミナー実行委員会, 第1回フロンティア太陽電池セミナー優秀ポスター賞
• 30 May 2019

  高分子学会, 高分子研究奨励賞
• 12 Jul. 2019

  高分子学会関西支部, ヤングサイエンティスト講演賞

External funds: Kakenhi

• ドナー/アクセプター界面における動的エキシトンの高速電荷分離メカニズムの解明

  Grant-in-Aid for Transformative Research Areas (A)

  Transformative Research Areas, Section (II)

  Kyoto University

  玉井 康成

  From 10 Sep. 2021, To 31 Mar. 2023, Adopted

  https://kaken.nii.ac.jp/grant/KAKENHI-PUBLICLY-21H05394/
• Offset-less charge generation due to symmetry breaking in pi-conjugated molecular systems

  Grant-in-Aid for Scientific Research (A)

  Medium-sized Section 35:Polymers, organic materials, and related fields

  Kyoto University

  大北 英生

  From 05 Apr. 2021, To 31 Mar. 2026, Granted

  電荷生成;オフセットレス;エントロピー;エンタルピー;自発的対称性の破れ

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21H04692/
• 電子ドナー/アクセプター界面における究極的に「無駄」の無い電荷分離の実現

  Grant-in-Aid for Scientific Research (B)

  Basic Section 35030:Organic functional materials-related

  Kyoto University

  玉井 康成

  From 01 Apr. 2021, To 31 Mar. 2024, Granted

  有機薄膜太陽電池;高速分光;電荷分離;電荷再結合

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21H02012/
• Improvement in Conductive Properties of Conjugated Polymer Blended in Insulating Polymer

  Grant-in-Aid for Challenging Research (Exploratory)

  Medium-sized Section 35:Polymers, organic materials, and related fields

  Kyoto University

  Hideo OHKITA

  From 28 Jun. 2019, To 31 Mar. 2021, Project Closed

  共役高分子;絶縁性高分子;結晶;非晶;相溶性;分子量;表面エネルギー;太陽電池;結晶性共役高分子;ブレンド膜;電荷輸送特性;分子量依存性;ブレンド;非晶性;結晶性;正孔輸送;移動度;電荷輸送;電流計測原子間力顕微鏡

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-19K22217/
• Exploratory Study on Conjugated Polymers with Highly Efficient Singlet Fission

  Grant-in-Aid for Challenging Research (Exploratory)

  Kyoto University

  Hideo OHKITA

  From 30 Jun. 2017, To 31 Mar. 2019, Project Closed

  一重項分裂;共役高分子;J凝集;H凝集;分子内D-A;分子内Ｄ－Ａ;結晶性共役高分子;分子鎖内;分子鎖間;三重項励起子対;三重項励起子解離;励起子拡散定数;結晶;非晶;分子内電荷移動;三重項励起子;ポーラロン;結晶性

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17K19157/
• Charge dynamics in planar heterojunctions

  Grant-in-Aid for Young Scientists (B)

  Kyoto University

  Yasunari Tamai

  From 01 Apr. 2017, To 31 Mar. 2019, Project Closed

  有機薄膜太陽電池;過渡吸収分光法;電荷分離;電荷再結合;共役高分子;光電変換;超短パルス分光;過渡吸収分光;ヘテロジャンクション

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17K14527/
• Exciton Dynamics in Crystalline Domains of Conjugated Polymers

  Grant-in-Aid for Scientific Research (A)

  Kyoto University

  Hideo OHKITA

  From 01 Apr. 2014, To 31 Mar. 2019, Project Closed

  一重項励起子拡散;共役高分子;励起子相互作用;J凝集;H凝集;結晶性;励起子拡散;次元性;超放射;一重項分裂;結晶性共役高分子;結晶化度;一重項励起子;三重項励起子;分子内電荷移動;励起子拡散定数;励起子カップリング;振動緩和;非緩和励起子;ダイナミクス;フェルスター

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26248033/

External funds: others

• スパース解析と遺伝的アルゴリズムの融合による新奇スペクトル分離手法の開発

  JSTさきがけ

  From 01 Oct. 2018, To 31 Mar. 2021

  代表

Education

Teaching subject(s)

• From Apr. 2017, To Mar. 2018

  Polymer Physical Properties

  Spring, 工学研究科
• From Apr. 2018, To Mar. 2019

  Fundamental Chemical Experiments

  Spring, 全学共通科目
• From Apr. 2018, To Mar. 2019

  Polymer Physical Properties

  Spring, 工学研究科
• From Apr. 2019, To Mar. 2020

  Polymer Physical Properties

  Spring, 工学研究科
• From Apr. 2020, To Mar. 2021

  Polymer Physical Properties

  Spring, 工学研究科
• From Apr. 2021, To Mar. 2022

  Polymer Physical Properties

  Spring, 工学研究科

Student achievements: Awards

• 2016KIPS若手高分子シンポジウム優秀ポスター発表賞

  奥山拓夢, KIPS委員会, 09 Dec. 2016
• 平成29年度吉田卒業研究・論文賞

  吉高一輝, 京都大学, 09 Jun. 2017
• 第67回高分子学会年次大会優秀ポスター賞

  村田恭大, 高分子学会, 05 May 2018
• 2018KIPS若手高分子シンポジウム　優秀ポスター賞

  吉高一輝, KIPS委員会, 14 Dec. 2018
• 令和元年度吉田卒業研究・論文賞

  齋藤俊晴, 京都大学工学研究科, 26 Jun. 2019