Synthesis and photophysical properties of two dual oligothiophene-fullerene linkage molecules as photoinduced long-distance charge separation systems

Masashi Narutaki, Kazuo Takimiya, Tetsuo Otsubo, Yutaka Harima, Huimin Zhang, Yasuyuki Araki, Osamu Ito

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

To further extend photoinduced charge separation previously observed for oligothiophene-fullerene dyads (nT-C60), we have studied two novel dual oligothiophene-fullerene triads, 8T-4T-C60 and 4T-ST-C 60, where quaterthiophene (4T) and octithiophene (8T) are linked by a trimethylene chain and either one is attached to a fullerene (C60). The cyclic voltammograms and electronic absorption spectra of these triad compounds indicated no electronic interactions among the three components. On the other hand, the emission spectra were markedly perturbed by electron transfer and/or energy transfer from the oligothiophene to fullerene. Detailed comparisons between the emission spectra of the triads (8T-4T-C60 and 4T-8T-C60) and the dyads (4T-C60 and 8T-C60) suggest that the additionally attached octithiophene or quaterthiophene in the triads is involved in the photophysical decay mechanism, and the 8T-4T-C 60 triad undergoes photoinduced electron transfer leading to long-distance charge separation. This was actually corroborated by observation of the specific bands due to 8T.+-4T-C60.- species in the transient absorption spectra after photoexcitation of the octithiophene. The sandwich device based on the 8T-4T-C60 triad produced a more effective photovoltaic response to visible light owing to the contribution of the additional octithiophene chromophore compared to that using the dyad 4T-C60. On the other hand, the 4T-8T-C60-based device demonstrated a rather poorer photovoltaic performance when compared to the ST-C60 device.

Original languageEnglish
Pages (from-to)1761-1768
Number of pages8
JournalJournal of Organic Chemistry
Volume71
Issue number5
DOIs
Publication statusPublished - 2006 Mar 5

ASJC Scopus subject areas

  • Organic Chemistry

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