title: Ultrafast charge separation at a polymer-single-walled carbon nanotube molecular junction.
abstract: We have investigated the charge photogeneration dynamics at the interface formed between single-walled carbon nanotubes (SWNTs) and poly(3-hexylthiophene) (P3HT) using a combination of femtosecond spectroscopic techniques. We demonstrate that photoexcitation of P3HT forming a single molecular layer around a SWNT leads to an ultrafast (∼430 fs) charge transfer between the materials. The addition of excess P3HT leads to long-term charge separation in which free polarons remain separated at room temperature. Our results suggest that SWNT-P3HT blends incorporating only small fractions (1%) of SWNTs allow photon-to-charge conversion with efficiencies comparable to those for conventional (60:40) P3HT-fullerene blends, provided that small-diameter tubes are individually embedded in the P3HT matrix.
authors.affiliation: Department of Physics, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, U.K.
authors.forename: Samuel D
authors.initials: SD
authors.lastname: Stranks
authors.forename: Christian
authors.initials: C
authors.lastname: Weisspfennig
authors.forename: Patrick
authors.initials: P
authors.lastname: Parkinson
authors.forename: Michael B
authors.initials: MB
authors.lastname: Johnston
authors.forename: Laura M
authors.initials: LM
authors.lastname: Herz
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Nicholas