2023 Fiscal Year Final Research Report
Elucidation of photoionization process in condensed phase by using multiple excitation and development to high-efficiency electron transfer process
| Project/Area Number |
21H01889
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 32010:Fundamental physical chemistry-related
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| Research Institution | Osaka University |
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Principal Investigator |
Miyasaka Hiroshi 大阪大学, エマージングサイエンスデザインR3センター, 特任教授 (40182000)
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| Co-Investigator(Kenkyū-buntansha) |
五月女 光 大阪大学, 大学院基礎工学研究科, 助教 (60758697)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 電子移動 / 光イオン化 / 多重励起過程 / フェムト秒ダイナミクス / ピコ秒ダイナミクス / 多光子吸収 |
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| Outline of Final Research Achievements |
In the photoionization process in the condensed phase, the initial distance between the parent cation and the ejected electron has been estimated to be several nanometers. In the case that the electrons in such ionized states or their precursors can be quickly and efficiently captured by other molecules and, as a result, the long distance is fixed, it is expected that a high-energy level charge-separated state with a long interionic distance can be rapidly generated and, consequently, the charge recombination can be suppressed. In this research, we utilized highly electronic excited states generated by pulsed laser multiple excitation methods in various solution systems and realized the formation of charge-separated states with long interionic distances by the ultrafast (< 1 ps) electron capture. In addition, we have revealed the mechanism of the unique electronic state that enables low-energy ionization, and factors that determine the cation-electron distance.
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| Free Research Field |
物理化学、光化学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では、天然光合成系のZスキームと原理は異なるが、逐次２光子吸収によるイオン化を進行させ、放出電子を迅速かつ効率良く他分子に捕捉させ距離を固定化することで、後続の還元・酸化等の反応を誘起できる高エネルギーかつ再結合を抑制した電荷分離状態を高収率で実現した。これは、光エネルギー変換や人工光合成にも深く関わる光誘起電子移動反応におけるエネルギーギャップ則の制限により、従来は困難であった(1) 迅速な電荷分離反応、(2) 高エネルギーな電荷分離状態、(3) 遅い再結合を同時に満足できる新手法であり、光誘起電子移動反応の利用に対して重要な方法を示した。
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