TY - JOUR
T1 - On the luminescence efficiency of polymer light-emitting diodes
T2 - A quantum-chemical investigation
AU - Beljonne, D.
AU - Shuai, Z.
AU - Cornil, J.
AU - Calbert, J. Ph
AU - Brédas, J. L.
N1 - Funding Information:
The work in Mons is partly supported by the Belgian Federal Services for Scientific, Technical, and Cultural Affairs (InterUniversity Attraction Pole, program PAl 4/11), the Belgian National Fund for Scientific Research (FNRS/FRFC), and the European Commission (BRITE-EURAM contract BRPR-CT97-0469 OSCA). J.C. and D.B. are research fellows of the Belgian National Fund for Scientific Research (FNRS). The work at the University of Arizona is supported in part by ONR through the MURI Center for Advanced Multiflinctional Polymers (CAMP).
PY - 2001/10/31
Y1 - 2001/10/31
N2 - Correlated quantum-chemical techniques are applied to the description of electronic excitations in luminescent conjugated polymers. We first address the role of intermolecular interactions on the emission properties of organic conjugated materials. The nature of the lowest excited states in molecular aggregates is discussed and a special emphasis is devoted to the chain-length dependence of the exciton coupling. By applying a molecular orbital perturbation approach, we then calculate the formation rates for singlet and triplet molecular excitons associated with intermolecular charge-transfer processes. 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.
AB - Correlated quantum-chemical techniques are applied to the description of electronic excitations in luminescent conjugated polymers. We first address the role of intermolecular interactions on the emission properties of organic conjugated materials. The nature of the lowest excited states in molecular aggregates is discussed and a special emphasis is devoted to the chain-length dependence of the exciton coupling. By applying a molecular orbital perturbation approach, we then calculate the formation rates for singlet and triplet molecular excitons associated with intermolecular charge-transfer processes. 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.
KW - Davydov splitting (DS)
KW - Light-emitting diodes (LED)
KW - Poly(paraphenylenevinylene) (PPV)
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U2 - 10.1016/S1010-6030(01)00379-3
DO - 10.1016/S1010-6030(01)00379-3
M3 - Article
AN - SCOPUS:0002248441
VL - 144
SP - 57
EP - 62
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
SN - 1010-6030
IS - 1
ER -