title: Influence of Energetic Disorder on Exciton Lifetime and Photoluminescence Efficiency in Conjugated Polymers.
abstract: Using time-resolved photoluminescence (TRPL) spectroscopy the exciton lifetime in a range of conjugated polymers is investigated. For poly(p-phenylenevinylene) (PPV)-based derivatives and a polyspirobifluorene copolymer (PSBF) we find that the exciton lifetime is correlated with the energetic disorder. Better ordered polymers exhibit a single exponential PL decay with exciton lifetimes of a few hundred picoseconds, whereas polymers with a larger degree of disorder show multiexponential PL decays with exciton lifetimes in the nanosecond regime. These observations are consistent with diffusion-limited exciton quenching at nonradiative recombination centers. The measured PL decay time reflects the time that excitons need to diffuse toward these quenching sites. Conjugated polymers with large energetic disorder and thus longer exciton lifetime also exhibit a higher photoluminescence quantum yield due to the slower exciton diffusion toward nonradiative quenching sites.
authors.affiliation: Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.|Dutch Polymer Institute , P.O. Box 902, 5600 AX Eindhoven, The Netherlands.
authors.forename: Irina
authors.initials: I
authors.lastname: Rörich
authors.affiliation: Lam Research Corporation , 4300 Cushing Pkwy, Fremont, California 94538, United States.
authors.forename: Oleksandr V
authors.initials: OV
authors.lastname: Mikhnenko
authors.affiliation: Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Gehrig
authors.affiliation: Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Paul W M
authors.initials: PW
authors.lastname: Blom
authors.affiliation: Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: N Irina
authors.identifier: 0000-0002-9717-8766
authors.initials: NI
authors.lastname: Crăciun