title: The impact of driving force on electron transfer rates in photovoltaic donor-acceptor blends.
abstract: The effect of acceptor energy level on electron transfer rate in blends of the polymer solar-cell material poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is studied using time-resolved fluorescence. Fast electron transfer in less than 2 ps is observed for a driving force between 0.2 and 0.6 eV and the electron transfer is slower outside this range. This dependence is described by Marcus theory with a reorganization energy of ≈0.4 eV.
authors.affiliation: Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Ward
authors.forename: Arvydas
authors.initials: A
authors.lastname: Ruseckas
authors.forename: Mohanad Mousa
authors.initials: MM
authors.lastname: Kareem
authors.forename: Bernd
authors.initials: B
authors.lastname: Ebenhoch
authors.forename: Luis A
authors.initials: LA
authors.lastname: Serrano
authors.forename: Manal
authors.initials: M
authors.lastname: Al-Eid
authors.forename: Brian
authors.initials: B
authors.lastname: Fitzpatrick
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Rotello
authors.forename: Graeme
authors.initials: G
authors.lastname: Cooke
authors.forename: Ifor D W
authors.initials: ID
authors.lastname: Samuel
keywords: PTB7; charge generation; excitonic solar cells; reorganization energy