Singlet fission in tetracene: an excited state analysis
| Autor: | Maximilian F. S. J. Menger, Shirin Faraji, Luis Enrique Aguilar Suarez |
|---|---|
| Přispěvatelé: | Theoretical Chemistry |
| Rok vydání: | 2020 |
| Předmět: |
Biophysics
010402 general chemistry 01 natural sciences chemistry.chemical_compound 0103 physical sciences Physical and Theoretical Chemistry EXCHANGE Molecular Biology Potential mechanism exciton analysis Physics 010304 chemical physics Singlet fission Charge (physics) Condensed Matter Physics tetracene 0104 chemical sciences Tetracene chemistry Chemical physics Excited state exciton descriptors Current (fluid) Mechanism (sociology) PACKAGE |
| Zdroj: | Molecular Physics, 118(21-22):e1769870. Taylor & Francis Ltd |
| ISSN: | 1362-3028 0026-8976 |
| Popis: | Singlet fission is a potential mechanism to enhance the performance of current solar cells. However, the actual mechanism is still a matter of debate, with charge transfer states believed to play an essential role. The probability of the overall process can be related to the electronic coupling between the electronic states. Here, we explore the excited states of three pairs of tetracene with different relative orientation in the crystal structure showing different electronic couplings and identify the role of charge transfer states. First, a suitable theoretical method for the study of the tetracene pairs is determined by comparing time-dependent density functional theory with wave function-based methods in terms of excitation energies, so-called exciton descriptors, and graphical tools such as electron-hole correlation plots and natural transition orbitals. The results show the presence of low-lying charge transfer states in those tetracene pairs with non-zero electronic coupling, suggesting a superexchange-mediated mechanism, and high-lying charge resonance states for the pair with zero electronic coupling. Finally, the lower electron-hole correlation coefficients for pairs with non-zero coupling speak in favour of the superexchange-mediated mechanism, as a weaker Coulombic attraction due to the mixing with charge transfer states further facilitates the formation of the (Formula presented.) state from the photoexcited molecule. |
| Databáze: | OpenAIRE |
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