Direct observation of charge-transfer dynamics in a conjugated conducting polymer poly (3-octylthiophene)-fullerene composite by time-resolved infrared spectroscopy

J. Wang, Y. Li, X. Hong, M. A. El-Sayed*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Transient infrared-active vibrational (IRAV) modes observed in the π-conjugated conducting polymers upon photoexcitation are usually used to characterize the dynamics of the photoinduced charge separation and recombination processes. In this paper, the dynamic behavior of photogenerated charge carrier in the poly(3octylthiophene) (P3OT) conducting polymer doped with fullerene (C60) has been studied by using step-scan time-resolved Fourier-transform infrared spectroscopy at room temperature in the 2500-900-cm-1 (0.310.11-eV) frequency region. Upon photoexcitation with a 10-ns laser pulses, it is observed that IRAV modes appear in the similar vibrational frequency regions for pure P3OT and C60-doped P3OT; however, the observed IRAV modes is enhanced by 800% in intensity in the presence of small amount of C60 (e.g., 10%). Our results also show that the charge separation occurs instantaneously within the laser pulse width (10 ns), whereas the charge recombination processes occur in the microseconds to a few milliseconds time domain. In addition, the observed enhancement in the IRAV modes upon C60 doping indicates an enhanced photogeneration efficiency of the charge separation.

Original languageEnglish (US)
Article number235413
Pages (from-to)2354131-2354135
Number of pages5
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume64
Issue number23
StatePublished - Dec 15 2001
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics

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