title: Subnanosecond geminate charge recombination in polymer-polymer photovoltaic devices.
abstract: We present direct spectroscopic evidence for substantial subnanosecond charge recombination in polymer-polymer blend photovoltaic devices. Early dynamics are dominated by exciton-charge interactions associated with high initial excitation densities. Independent of density, 30% of charges subsequently recombine geminately within just 2 nanoseconds, in contrast with fullerene blends. The remainder recombines with a half-life of approximately 200 ns. The morphological invariance of subnanosecond recombination suggests that its origin is inherent in the molecular structure at the polymer-polymer interface.
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge, CB3 0HE, United Kingdom. Justin.Hodgkiss@vuw.ac.nz
authors.forename: Justin M
authors.initials: JM
authors.lastname: Hodgkiss
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Campbell
authors.forename: R Alex
authors.initials: RA
authors.lastname: Marsh
authors.forename: Akshay
authors.initials: A
authors.lastname: Rao
authors.forename: Sebastian
authors.initials: S
authors.lastname: Albert-Seifried
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend