Spin-dependent electron-hole capture kinetics in luminescent conjugated polymers.
The recombination of electron-hole pairs injected in extended conjugated systems is modeled as a multistep interconversion relaxation in monoexcited electronic state space, mediated by electron-phonon coupling. The computed ratio of triplet-to-singlet exciton formation times r=tau(T)/tau(S) increases from 0.9 for a model dimer to 2.5 for a 32-unit chain, in good agreement with recent experiments. We rationalize the conjugation-length dependence of r in terms of spin-specific energetics and mutual vibronic coupling of the excited states.
Karabunarliev
Stoyan
S
Department of Chemistry and Center for Materials Chemistry, University of Houston, Texas 77204-5003, USA. karabunarliev@uh.edu
Bittner
Eric R
ER