2023 Fiscal Year Final Research Report
Importance of liquid crystallinity in realizing polymer-based organic field-effect transistors with high mobility and operational stability
| Project/Area Number |
20K05310
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 29010:Applied physical properties-related
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
SAKAMOTO Kenji 国立研究開発法人物質・材料研究機構, 高分子・バイオ材料研究センター, 主席研究員 (00222000)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 有機電界効果トランジスタ / 液晶性 / 高分子有機半導体 / 分子配向制御 / 動作安定性 / 電界効果移動度 / 素子間のばらつき / ドナー・アクセプター共重合体 |
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| Outline of Final Research Achievements |
This study was planned to demonstrate the usefulness of liquid crystalline (LC) materials in realizing polymer-based organic field-effect transistors (OFETs) with high mobility, high operational stability, and small device-to-device variation. Three p-type semiconducting polymers were selected in terms of two key words: LC and donor-acceptor copolymer, and OFETs with active layers of these polymers were fabricated. Unfortunately, we could not confirm the advantage of using LC polymers as active layer materials. However, during the course of this study, it was found that the charge transfer of mobile holes in the channel to the gate dielectric is one of the intrinsic origins caused operational instability in OFETs. This charge transfer can be suppressed by increasing the highest occupied molecular orbital level mismatch between the active layer and gate dielectric. This knowledge provides a guideline to realize p-channel OFETs with high operational stability.
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| Free Research Field |
有機エレクトロニクス
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| Academic Significance and Societal Importance of the Research Achievements |
有機エレクトロニクスの駆動・信号処理を担う有機電界効果トランジスタ（OFET）の性能を表す重要な指標は電界効果移動度であり、その向上には目覚ましいものがあった。しかしながら、この単純な移動度競争を終わりにしてOFETの実用化に向け、動作安定性、素子間のばらつき低減を含めた総合的な材料・プロセス技術の開発をする時期に来ている。本研究では、薄膜トランジスタ構造に固有な動作不安定性の起源を明らかにし、高動作安定OFETを実現するための有機半導体と絶縁膜の新規材料設計および材料選択に関する指針を得た。
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