Study and control of long-range exciton transport in organic and hybrid nanostructures for future exciton-based electronics

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18927
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Vacha Martin 東京工業大学, 物質理工学院, 教授 (50361746)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: exciton transport / fluorescence microscopy

Outline of Final Research Achievements

Exciton transport in molecular and supramolecular structures was studied with the aim of understanding the key factors for long-range exciton transport in mesoscopic organic and hybrid systems. Simultaneous measurements by fluorescence and atomic force microscopy on self-assembled supramolecular nanofibers and their bundles showed that 3-dimensional mesostructures function as efficient light waveguides. On the other hand, 1-dimensional nanofibers exhibit long exciton diffusion lengths on the order of several hundreds of nanometers. Such large diffusion length values were explained by the formation of oblique molecular aggregates between individual monomers within the nanofibers. Further, the effect of topology on the exciton diffusion was studied using self-assembled supramolecular nanorings. Absorption and fluorescence polarization anisotropy together with theoretical simulations showed that the exciton transport along the nanorings is limited to several nanometers.

Free Research Field

Organic materials nanoscience

Academic Significance and Societal Importance of the Research Achievements

研究成果の科学的意義は、自己組織化超分子ナノファイバー内での長距離励起子輸送の発見にある。 このような長距離での励起子拡散の報告は他に数件しかなく、本成果は、この現象が斜めの分子集合体の存在によって起こることを初めて解明した。また、本研究の社会的意義は、電流の代わりに励起子輸送によって駆動される励起子エレクトロニクス分野の基礎原理を探求することである。