Ultrafast Spectroscopic Signature of Charge Transfer between Single-Walled Carbon Nanotubes and C60

Anne Marie Dowgiallo, Kevin S. Mistry, Justin C. Johnson, Jeffrey L. Blackburn

Research output: Contribution to journalArticlepeer-review

63 Scopus Citations

Abstract

The time scales for interfacial charge separation and recombination play crucial roles in determining efficiencies of excitonic photovoltaics. Near-infrared photons are harvested efficiently by semiconducting single-walled carbon nanotubes (SWCNTs) paired with appropriate electron acceptors, such as fullerenes (e.g., C60). However, little is known about crucial photochemical events that occur on femtosecond to nanosecond time scales at such heterojunctions. Here, we present transient absorbance measurements that utilize a distinct spectroscopic signature of charges within SWCNTs, the absorbance of a trion quasiparticle, to measure both the ultrafast photoinduced electron transfer time (τpet) and yield (φpet) in photoexcited SWCNT-C60 bilayer films. The rise time of the trion-induced absorbance enables the determination of the photoinduced electron transfer (PET) time of τpet ≤ 120 fs, while an experimentally determined trion absorbance cross section reveals the yield of charge transfer (φpet ≈ 38 ± 3%). The extremely fast electron transfer times observed here are on par with some of the best donor:acceptor pairs in excitonic photovoltaics and underscore the potential for efficient energy harvesting in SWCNT-based devices.

Original languageAmerican English
Pages (from-to)8573-8581
Number of pages9
JournalACS Nano
Volume8
Issue number8
DOIs
StatePublished - 26 Aug 2014

NREL Publication Number

  • NREL/JA-5900-62299

Keywords

  • charge generation
  • electron transfer
  • exciton dissociation
  • fullerene
  • photovoltaic
  • recombination
  • single-walled carbon nanotubes
  • trion

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