Singlet and triplet exciton formation rates in conjugated polymer light-emitting diodes
By applying a molecular orbital perturbation approach, we calculate the formation rates for singlet and triplet molecular excitons associated with intermolecular charge-transfer processes. It is found that the interchain bond-charge correlation has a strong influence on the relative probabilities for generating singlet and triplet excitons. Most importantly, application of our approach to a model system for poly-(paraphenylenevinylene) shows that the ratio between the electroluminescence and photoluminescence quantum yields generally exceeds the 25% spin-degeneracy statistical limit.
Shuai
Z
Centre de Recherche en Electronique et Photonique Moleculaires Service de Chimie des Materiaux Nouveaux, Universite de Mons-Hainaut, Place du Parc 20, B-7000 Mons, Belgium.
Beljonne
D
Silbey
RJ
Bredas
JL