Abstract
It has been found in recent measurements that the singlet-to-triplet exciton ratio in organic light-emitting diodes (OLEDs) is larger than expected from spin degeneracy, and that singlet excitons form at a larger rate than triplets. We employed the technique of optically detected magnetic resonance to measure the spin-dependent exciton formation rates in films of a polymer and corresponding monomer, and explore the relation between the formation rates and the actual singlet-to-triplet ratio measured previously in OLEDs. We found that the spin-dependent exciton formation rates can indeed quantitatively explain the observed exciton yields, and that singlet formation rates and yields are significantly enhanced only in polymer OLEDs, but not in OLEDs made from the corresponding monomer.
| Original language | English |
|---|---|
| Pages (from-to) | 1-4 |
| Number of pages | 4 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 70 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - Dec 2004 |
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ASJC Scopus subject areas
- Condensed Matter Physics
Cite this
Spectroscopic study of spin-dependent exciton formation rates in π-conjugated semiconductors : Comparison with electroluminescence techniques. / Yang, C.; Vardeny, Z. V.; Köhler, A.; Wohlgenannt, M.; Al-Suti, M. K.; Khan, M. S.
In: Physical Review B - Condensed Matter and Materials Physics, Vol. 70, No. 24, 12.2004, p. 1-4.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Spectroscopic study of spin-dependent exciton formation rates in π-conjugated semiconductors
T2 - Comparison with electroluminescence techniques
AU - Yang, C.
AU - Vardeny, Z. V.
AU - Köhler, A.
AU - Wohlgenannt, M.
AU - Al-Suti, M. K.
AU - Khan, M. S.
PY - 2004/12
Y1 - 2004/12
N2 - It has been found in recent measurements that the singlet-to-triplet exciton ratio in organic light-emitting diodes (OLEDs) is larger than expected from spin degeneracy, and that singlet excitons form at a larger rate than triplets. We employed the technique of optically detected magnetic resonance to measure the spin-dependent exciton formation rates in films of a polymer and corresponding monomer, and explore the relation between the formation rates and the actual singlet-to-triplet ratio measured previously in OLEDs. We found that the spin-dependent exciton formation rates can indeed quantitatively explain the observed exciton yields, and that singlet formation rates and yields are significantly enhanced only in polymer OLEDs, but not in OLEDs made from the corresponding monomer.
AB - It has been found in recent measurements that the singlet-to-triplet exciton ratio in organic light-emitting diodes (OLEDs) is larger than expected from spin degeneracy, and that singlet excitons form at a larger rate than triplets. We employed the technique of optically detected magnetic resonance to measure the spin-dependent exciton formation rates in films of a polymer and corresponding monomer, and explore the relation between the formation rates and the actual singlet-to-triplet ratio measured previously in OLEDs. We found that the spin-dependent exciton formation rates can indeed quantitatively explain the observed exciton yields, and that singlet formation rates and yields are significantly enhanced only in polymer OLEDs, but not in OLEDs made from the corresponding monomer.
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U2 - 10.1103/PhysRevB.70.241202
DO - 10.1103/PhysRevB.70.241202
M3 - Article
VL - 70
SP - 1
EP - 4
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 24
ER -