フェムト秒レーザーで1本のナノファイバー中の励起子拡散を可視化～独自開発したフェムト秒顕微分光装置による有機半導体ナノ構造における光エネルギー移動の直接観測～

2025-11-27 愛媛大学

＜関連情報＞

• https://www.ehime-u.ac.jp/data_relese/pr_20251127_eng/
• https://www.ehime-u.ac.jp/wp-content/uploads/2025/11/pr_20251127_eng.pdf
• https://pubs.acs.org/doi/10.1021/acs.jpclett.5c02998

個々の銅フタロシアニンナノファイバーにおける励起子拡散のフェムト秒単粒子分光法 Femtosecond Single-Particle Spectroscopy of Exciton Diffusion in Individual Copper Phthalocyanine Nanofibers

Yukihide Ishibashi,Yuto Shiraishi,Miyu Morita,Ryo Kihara,Tsuyoshi Asahi
The Journal of Physical Chemistry Letters  Published: October 31, 2025
DOI:https://doi.org/10.1021/acs.jpclett.5c02998

Abstract

Exciton diffusion in individual copper phthalocyanine (CuPc) nanofibers of β- and η-crystalline phases was investigated using femtosecond single-particle spectroscopy. The exciton diffusion coefficient (D) ranged from 1.6 × 10^–5 to 0.079 cm² s^–1 for β-CuPc and from 0.040 to 0.48 cm² s^–1 for η-CuPc, with the η phase showing an average D (0.16 cm² s^–1) nearly ten times larger than that of the β phase (0.020 cm² s^–1). The enhanced transport in η-CuPc is attributed to a stronger excitonic coupling and greater intermolecular overlap. The broad distributions of D within each phase strongly correlated with nanofiber size, with longer fibers exhibiting reduced diffusion, likely due to molecular packing misalignments and shape-induced electronic variations. These findings highlight the essential roles of the crystalline phase and morphology in governing exciton transport in organic nanostructures.