Fluorescence Up-Conversion Study of Excitation Energy Transport Dynamics in Oligothiophene-Fullerene Linked Dyads

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• 作者：Takumi Nakamura ; Yasuyuki Araki ; Osamu Ito ; Kazuo Takimiya ; Tetsuo Otsubo
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：February 14, 2008
• 年：2008
• 卷：112
• 期：6
• 页码：1125 - 1132
• 全文大小：159K
• 年卷期：v.112,no.6(February 14, 2008)
• ISSN：1520-5215

文摘

Photoinduced excitation energy transport dynamics in oligothiophene-fullerene linked dyads, nT-C₆₀(n = 4, 8, and 12), have been investigated by femtosecond fluorescence up-conversion. In 8T-C₆₀ and 12T-C₆₀, each time profile of the fluorescence due to the ¹nT* moiety consists of two components. The sub-picosecond component and a few picosecond components were experimentally evaluated depending on thelengths of oligothiophenes (n =8 and 12) and on the analyzing wavelength of the fluorescence. However, thetime trace of the fluorescence due to ¹4T*-C₆₀ decayed with a single short component in ~300 fs due todirect excited energy transfer (EET) from the ¹4T* moiety to the C₆₀ moiety. On the basis of the kineticmodels considering the short and long locally -conjugative thiophene segments in 8T-C₆₀ and 12T-C₆₀, therate parameters of the elemental processes were evaluated. Sub-picosecond time constants of nT-C₆₀ werefound to be EET from the thiophene segment vicinal to the C₆₀ moiety and intrachain energy transfer. Slowerpicosecond dynamics mainly corresponds to EET from the thiophene segments apart from the C₆₀ moiety.