Elucidation of Photoexcited Dynamics at the Photochromic Surface Using Femtosecond Electronic Sum-Frequency Generation Spectroscopy

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K14180
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: Osaka University
• Principal Investigator: Sotome Hikaru 大阪大学, 基礎工学研究科, 助教 (60758697)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: フォトクロミック分子 / 超高速分光 / 電子和周波発生分光 / 光機能

Outline of Final Research Achievements

Photochromic reactions at the surface play an important role in photoswitching of physical properties and control of molecular orientation at the surface. For elucidation of photoinduced responses and functions of photofunctional materials, we constructed an apparatus for femtosecond time-resolved electronic sum-frequency generation spectroscopy and applied it to observation of ultrafast isomerization reactions of photochromic molecules to reveal its molecular mechanism and factors for dominating the overall reactions. We selected photochromic samples suitable to the measurements at the surface by using transient absorption and time-resolved vibrational spectroscopies. In the measurements at the surface, we introduced a rotational sample stage to avoid degradation of samples and perform the stable measurements. A series of attempts in the present study paved a way to applications of this time-resolved technique to a variety of sample systems such as functional materials.

Free Research Field

分子分光学

Academic Significance and Societal Importance of the Research Achievements

本研究の主眼であるフォトクロミック分子系は、表面物性の光スイッチングや液晶分子配向において界面機能を担っており、これまではバルク溶液における光計測から明らかになった反応速度や反応量子収率などの知見をもとに材料設計がなされてきたが、これを表面にあるがままの形態で計測することをめざした本研究の分光計測技術の開発や得られた成果は、表面・界面の材料物性研究の足がかりになると考えられる。