title: Recombination dynamics of charge pairs in a push-pull polyfluorene-derivative.
abstract: We investigate the properties of long-lived species in F8BT films through time-resolved photoluminescence (PL) measurements at room temperature and 10 K. The kinetics consist of an initial exponential decay (τ = 2.26 ns) followed by a weak power-law decay (I(t) [proportionality] t(-1)) up to at least 1 ms, both of which depend weakly on temperature. From fluence-dependent PL and ultrafast transient absorption (TA) measurements, we confirm that this emission arises from the recombination of geminate charge-pairs generated through singlet-singlet annihilation. This behavior is a consequence of the donor-acceptor nature of this polymer, which enhances singlet-singlet annihilation and facilitates the formation of long-lived geminate-pairs from energetic singlet states.
authors.affiliation: Département de Physique & Regroupement Québécois sur les Matériaux de Pointe, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada. sg559@cam.ac.uk
authors.forename: Simon
authors.initials: S
authors.lastname: Gélinas
authors.forename: James
authors.initials: J
authors.lastname: Kirkpatrick
authors.forename: Ian A
authors.initials: IA
authors.lastname: Howard
authors.forename: Kerr
authors.initials: K
authors.lastname: Johnson
authors.forename: Mark W B
authors.initials: MW
authors.lastname: Wilson
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Pace
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
authors.forename: Carlos
authors.initials: C
authors.lastname: Silva