Gespeichert in:
| Hauptverfasser: | , , |
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| Format: | Recurso digital |
| Sprache: | |
| Veröffentlicht: |
Zenodo
2018
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| Online-Zugang: | https://doi.org/10.1038/s41598-018-21980-z |
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Inhaltsangabe:
- <p>Charge separation is a critical process for achieving high efficiencies in organic photovoltaic cells.<br>The initial tightly bound excitonic electron-hole pair has to dissociate fast enough in order to avoid<br>photocurrent generation and thus power conversion efficiency loss via geminate recombination. Such<br>process takes place assisted by transitional states that lie between the initial exciton and the free<br>charge state. Due to spin conservation rules these intermediate charge transfer states typically have<br>singlet character. Here we propose a donor-acceptor model for a generic organic photovoltaic cell<br>in which the process of charge separation is modulated by a magnetic field which tunes the energy<br>levels. The impact of a magnetic field is to intensify the generation of charge transfer states with<br>triplet character via inter-system crossing. As the ground state of the system has singlet character,<br>triplet states are recombination-protected, thus leading to a higher probability of successful charge<br>separation. Using the open quantum systems formalism we demonstrate that the population of triplet<br>charge transfer states grows in the presence of a magnetic field, and discuss the impact on carrier<br>population and hence photocurrent, highlighting its potential as a tool for research on charge transfer<br>kinetics in this complex systems.</p>