The time scales for interfacial charge separation and recombination play crucial roles in determining the 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). I will discuss 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 demonstrate the potential for efficient energy harvesting in SWCNT-based devices.

Ultrafast spectroscopic signature of charge transfer between single-walled carbon nanotubes and C60

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.