Abstract
The exciton-dissociation and charge-recombination processes in organic solar cells based on pentacene/C60 heterojunctions are investigated by means of quantum-mechanical calculations. The electronic couplings and the rates of exciton dissociation and charge recombination have been evaluated for several geometrical configurations of the pentacene/C60 complex, which are relevant to bilayer and bulk heterojunctions. The results suggest that, irrespective of the actual pentacene-fullerene orientation, both pentacene-based and C60-based excitons are able to dissociate efficiently. Also, in the case of parallel configurations of the molecules at the pentacene/C60 interface, the decay of the lowest charge-transfer state to the ground state is calculated to be very fast; as a result, it can compete with the dissociation process into mobile charge carriers. Since parallel configurations are expected to be found more frequently in bulk heterojunctions than in bilayer heterojunctions, the performance of pentacene/C60 bulk-heterojunction solar cells is likely to be more affected by charge recombination than that of bilayer devices.
Original language | English (US) |
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Pages (from-to) | 15777-15783 |
Number of pages | 7 |
Journal | Journal of the American Chemical Society |
Volume | 131 |
Issue number | 43 |
DOIs | |
State | Published - Nov 4 2009 |
Externally published | Yes |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledged KAUST grant number(s): KUS-C1-015-21
Acknowledgements: We acknowledge stimulating discussions with Prof. Bernard Kippelen and his research group and with Drs. D. Beljonne and J. Cornil. This work has been partially supported by the Center for Advanced Molecular Photovoltaics (Award No KUS-C1-015-21 made by King Abdullah University of Science and Technology, KAUST), Solvay, and the National Science Foundation under the STC Program (Award No DMR-0120967).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- General Chemistry
- Biochemistry
- Catalysis
- Colloid and Surface Chemistry