| 研究課題/領域番号 |
21K18927
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| 研究機関 | 東京工業大学 |
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研究代表者 |
VACHA Martin 東京工業大学, 物質理工学院, 教授 (50361746)
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| 研究期間 (年度) |
2021-07-09 – 2023-03-31
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| キーワード | 励起子輸送 |
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| 研究実績の概要 |
The purpose of this research is to study long-range exciton transport in mesoscopic organic and hybrid structures. Efficient transport of excitons over long distances is crucial in the function of light-harvesting systems, and is a key factor for realization of future exciton-based molecular electronics. The main objectives of the research are to understand the key design principles for long-range exciton transport in mesoscopic structures, including the roles of topology and dimensionality, and to discover ways to actively control the key factors of the exciton transport efficiency for advanced applications.
In the past year, the research concentrated on the detection of exciton transport in molecular fibers self-assembled from derivatives of the small molecule tris(phenylisoxazolyl)benzene. The self-assembly creates bundles of fibers tens to hundreds of micrometers in lengths. The preparation was optimized in terms of fiber thickness to avoid waveguiding effects that would overwhelm the exciton transport. Using a combined atomic force and fluorescence confocal microscopy, spatial profiles of fluorescence signal were measured on thin molecular fibers and the profiles were used to analyze an average exciton diffusion length. The analysis provided surprisingly large exciton diffusion lengths on the order of few hundreds of nm.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The study of the long-range exciton transport along pseudo one-dimensional molecular mesostructures proceeded mainly according to the original plan. In particular, the large exciton diffusion lengths are promising results for the possible future applications. On the other hand, study of the roles of topology and dimensionality was hampered by the difficulty of international collaborations due to the covid restrictions.
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| 今後の研究の推進方策 |
This year, the study of exciton transport in molecular fibers will continue, with an emphasis on time-resolved detection of the exciton diffusion. This will be achieved using time-correlated single photon counting with an avalanche photodiode (APD) mounted on an a piezostage. The molecular fiber will be excited with a focused laser beam in a confocal mode and fluorescence lifetimes will be measured along the fiber at varying distances from the excitation spot. In addition, the effects of topology in exciton diffusion will be examined on supramolecular toroidal nano- and mesostructures, starting with ring structures. As the size of the ring is smaller than the microscope resolution, the exciton transport will be monitored by measuring excitation and emission dynamic polarization anisotropy. Apart from the toroidal structures, novel linear supramolecular mesostructures will be considered to uncover the role of the building block arrangement in the exciton transport.
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| 次年度使用額が生じた理由 |
Travel expenses could not be used due to covid restrictions on business trips. Several conference participations are planned for this year.
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