有機電界効果デバイス界面の電子・スピン機能とその制御

2010 Fiscal Year Annual Research Report

• Project/Area Number: 22340080
• Research Institution: Nagoya University
• Principal Investigator: 黒田 新一 名古屋大学, 大学院・工学研究科, 教授 (20291403)
• Co-Investigator(Kenkyū-buntansha): 伊東 裕 名古屋大学, 大学院・工学研究科, 准教授 (10260374) ; 田中 久暁 名古屋大学, 大学院・工学研究科, 助教 (50362273) ; 丸本 一弘 筑波大学, 大学院・数理物質科学科, 准教授 (50293668) ; 下位 幸弘 産業技術総合研究所, ナノシステム研究部門, 主任研究員 (70357226)
• Keywords: 有機半導体 / 電界注入 / 電子スピン共鳴 / ルブレン / ペンタセン / フラーレン / ポリアルキルチオフェン / ポーラロン

Research Abstract

本年度は、電場誘起電子スピン共鳴(FI-ESR)法を以下の有機デバイスに適用した。
1. 名古屋大の永野らと共同し、ポリヘキシルチオフェン(P3HT)の単分子配向膜FETを作製した。FET移動度は高分子主鎖方向でπ-スタック方向よりも数倍高い値を示した。また、キャリヤ(ポーラロン)のFI-ESR信号の角度依存性から、高分子鎖方向、π-スタック方向、及び基板法線方向で異なるg値・線幅が得られた。g値・線幅の異方性や分子配向分布を考慮したスペクトルシミュレーションでFI-ESR信号はよく再現され、高分子鎖の一軸配向性がミクロに明らかとなった。さらに、決定された斜方対称的なg値は、DFT計算の結果とよく一致した。
2. 両極性FET材料として期待されるRR-P3HT/PCBM複合体FETのFI-ESR測定を行った。高分子上の正ポーラロンの信号は異方的であり、上記の配向膜で得られたg値、線幅等のパラメータを用いて分子配向性が精度よく決定された。その結果、PCBMを高濃度に複合化すると、界面でラメラ構造を形成していたP3HT分子のチオフェン環が基板と平行となる、flat-on配向が部分的に形成されることが示された。このことは、PCBM濃度の上昇に伴い正キャリヤのFET移動度が減少する原因の一つと考えられる。
3. 大阪大の竹谷教授、東大の岩佐教授らと共同し、ルブレン単結晶のFI-ESR観測を行った。界面の化学修飾により移動度の異なるデバイスを作製した結果、motional narrowing効果により尖鋭化したFI-ESR線幅と、FET移動度の間に明瞭な相関性が見出された、ESR線幅の解析から、キャリヤのトラップ時間が短いほどFET移動度が高くなることが明らかになった。
上記に加え、P3HT/PCBM複合体の光キャリヤの4分子再結合過程の解明や、有機半導体の2次元格子におけるポーラロンの広がりの理論計算等を進めた。

Research Products

• [Journal Article] Direct determination of interfacial molecular orientations in field-effect devices of P3HT/PCBM composites by electron spin resonance (2011)
  • Author(s): S.Watanabe, H.Tanaka, H.Ito, S.Kuroda, T.Mori, K.Marumoto, Y.Shimoi
  • Journal Title: Organic Electronics Volume: 12 Pages: 716-723
  • Peer Reviewed
• [Journal Article] Microscopic mechanisms behind the high mobility in rubrene single-crystal transistors as revealed by field-induced electron spin resonance (2011)
  • Author(s): K.Marumoto, J.Takeya, Y.Shimoi, H.Tanaka, S.Kuroda, T.Takenobu, Y.Iwasa, 他
  • Journal Title: Phys.Rev.B Volume: 83 Pages: 075302-1-075302-6
  • Peer Reviewed
• [Journal Article] Tight-Binding Study of Polarons in Two-Dimensional Systems : (2011)
  • Author(s): Jie Lei, Y, Shimoi
  • Journal Title: J.Phys.Soc.Jpn. Volume: 80 Pages: 034702-1-1034702-7
  • Peer Reviewed
• [Journal Article] Electron spin resonance observation of field-induced charge carriers in ultrathin-film transistors of regioregular poly(3-hexylthiophene) with controlled in-plane chain orientation (2010)
  • Author(s): S.Watanabe, H.Tanaka, S.Kuroda, A.Toda, S.Nagano, T.Seki, A.Kimoto, J.Abe
  • Journal Title: Appl.Phys.Lett. Volume: 96 Pages: 173302-1-173302-3
  • Peer Reviewed
• [Journal Article] Quadrimolecular recombination kinetics of photogenerated charge carriers in the composites of regioregular polythiophene derivatives and soluble fullerenes (2010)
  • Author(s): H.Tanaka, Y.Yokoi, N.Hasegawa, S.Kuroda, T.Iijima, T.Sato, T.Yamamoto
  • Journal Title: J.Appl.Phys Volume: 107 Pages: 083708-1-083708-9
  • Peer Reviewed
• [Presentation] DFT calculations of ESR g values in rubrene and oligoacenes : Implication to molecular orientation at interfaces in organic FETs (2011)
  • Author(s): Y.Shimoi, K.Marumoto, S.Kuroda
  • Organizer: 6th International Conference on Molecular Electronics and Bioelectronics (M&BE6)
  • Place of Presentation: Sendai, Japan
  • Year and Date: 2011-03-05
• [Presentation] DFT calculations of ESR g-values in organic FET materials (2010)
  • Author(s): Y.Shimoi, H.Tanaka, K.Marumoto, S.Kuroda
  • Organizer: 2010 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2010)
  • Place of Presentation: Honolulu, USA
  • Year and Date: 2010-12-19
• [Presentation] ESR Observation of Charge Carriers in Pentacene Field-Effect Transistcrs during Device Operation (2010)
  • Author(s): H.Tanaka, K.Kaneko, S.Watanabe, S.Kuroda, K.Marumoto, T.Takenobu, Y.Iwasa
  • Organizer: 7th Asia-Pacific EPR/ESR Symposium (APES2010)
  • Place of Presentation: Jeju, Korea
  • Year and Date: 2010-10-12
• [Presentation] Direct Determination of the In-Plane Chain Orientation in Charge Accumulation Layer of Regioregular Poly(3-hexylthiophene) Monolayer Transistors by ESR (2010)
  • Author(s): S.Kuroda, S.Watanabe, H.Tanaka, A.Toda, S.Nagano, T.Seki
  • Organizer: 7th Asia-Pacific EPR/ESR Symposium (APES2010)
  • Place of Presentation: Jeju, Korea
  • Year and Date: 2010-10-11
• [Presentation] ESR Spectroscopy of Field-Induced Charge Carriers in Organic Transistors (2010)
  • Author(s): S. Kuroda
  • Organizer: 13th International Conference on Organized Molecular Films (LB13)
  • Place of Presentation: Quebec, Canada
  • Year and Date: 2010-07-21
• [Presentation] Direct Determination of the In-Plane Chain Orientation in Charge Accumulation Layer of Regioregular Poly (3-Hexylthiophene) Monolayer Transistors by Electron Spin Resonance (2010)
  • Author(s): S.Watanabe, H.Tanaka, S.Kuroda, A.Toda, S.Nagano, T.Seki
  • Organizer: 13th International Conference on Organized Molecular Films (LB13)
  • Place of Presentation: Quebec, Canada
  • Year and Date: 2010-07-20
• [Presentation] ESR g-values of Organic FET materials : DFT Calculations (2010)
  • Author(s): Y.Shimoi, K.Marumoto, S.Kuroda
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010 (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-09
• [Presentation] Photocarrier Recombination in Surface-Type Photocells of Regioregular Poly(3-hexylthiophene)/ Fullerene Composites (2010)
  • Author(s): H.Ito, Y.Nishikawa, J.Suzuki, S.Watanabe, H.Tanaka, S.Kuroda
  • Organizer: International Conference on Science and Technology of Synthetic Metals (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-08
• [Presentation] Spatial Extent of Doping-Induced Hole Carriers in Very High-Mobility Rubrene Single Crystals (2010)
  • Author(s): N.Arai, K.Marumoto, K.Murakami, Y.Tominari, J.Takeya, Y. Shimoi, H.Tanaka, S.Kuroda, T.Takenobu，Y.Iwasa, 他
  • Organizer: International Conference on Science and Technology of Synthetic Metals (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-08
• [Presentation] On the Microscopic Mechanism of Very High Mobility in Organic Single-Crystal Transistors Directly Revealed by FI-ESR (2010)
  • Author(s): K.Marumoto, N.Arai, K.Murakami, Y.Tominari, J.Takeya, Y.Shimoi, H.Tanaka, S.Kuroda, T.Takenobu, Y.Iwasa, 他
  • Organizer: International Conference on Science and Technology of Synthetic Metals (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-08
• [Presentation] ESR Observations of Charge Carriers in Regioregular Poly(3-hexylthiophen) Field-Effect Transistors (2010)
  • Author(s): S.Kuroda
  • Organizer: International Conference on Science and Technology of Synthetic Metals (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-06
• [Presentation] ESR Observations of Field-Induced Polarons on Ultrathin-Film Transistors of Poly(3-hexylthiophene) with In-Plane Preferential Chain Orientations (2010)
  • Author(s): S.Watanabe, H.Tanaka, S.Kuroda, A.Toda, S.Nagano, T.Seki
  • Organizer: International Conference on Science and Technology of Synthetic Metals (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-06
• [Presentation] Polarons in Two-dimensional Organic FET Materials : Tight-binding Theory (2010)
  • Author(s): Jie Lei, Y.Shimoi
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010 (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-06
• [Presentation] Uniaxial Compression Effect on the Superconductivity of β-(BEDT-TTF)_2I_3 (2010)
  • Author(s): M.Niwa, H.Ito, S.Onari, Y.Tanaka, T.Hiramatsu, H.Yamochi, G.Saito, 他
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010 (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-05
• [Presentation] Electron Spin Resonance Observations of Charge Carriers and Molecular Orientations in Thin Films of Poly(p-phenylene vinylene) Derivatives (2010)
  • Author(s): Y.Bito, S.Watanabe, H.Tanaka, H.Ito, K.Marumoto, S.Kuroda
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010 (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-05
• [Presentation] Electron Spin Resonance Observation of Charge Carrier Concentrations in Organic Field-Effect Transistors during Device Operation (2010)
  • Author(s): H.Tanaka, S.Watanabe, H.Ito, K.Marumoto, S.Kuroda
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010 (ICSM2010)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2010-07-05