Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory
We present a multiscale model based on many-body Green’s functions theory in the GW approximation and the Bethe–Salpeter equation ( GW -BSE) for the simulation of singlet and triplet exciton transport in molecular materials. Dynamics of coupled electron–hole pairs are modeled as a sequence of incohe...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/ab7a04 |
| _version_ | 1827872900457168896 |
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| author | Jens Wehner Björn Baumeier |
| author_facet | Jens Wehner Björn Baumeier |
| author_sort | Jens Wehner |
| collection | DOAJ |
| description | We present a multiscale model based on many-body Green’s functions theory in the GW approximation and the Bethe–Salpeter equation ( GW -BSE) for the simulation of singlet and triplet exciton transport in molecular materials. Dynamics of coupled electron–hole pairs are modeled as a sequence of incoherent tunneling and decay events in a disordered morphology obtained at room temperature from molecular dynamics. The ingredients of the rates associated to the events, i.e. reorganization energies, site energies, lifetimes, and coupling elements, are determined from a combination of GW -BSE and classical polarizable force field techniques. Kinetic Monte Carlo simulations are then employed to evaluate dynamical properties such as the excitonic diffusion tensor and diffusion lengths. Using DCV5T-Me(3,3), a crystalline organic semiconductor, we demonstrate how this multiscale approach provides insight into the fundamental factors driving the transport processes. Comparing the results obtained via different calculation models, we investigate in particular the effects of charge-transfer mediated high exciton coupling and the influence of internal site energy disorder due to conformational variations. We show that a small number of high coupling elements indicative of delocalized exciton states does not impact the overall dynamics perceptively. Molecules with energies in the tail of the excitonic density of states dominate singlet decay, independent of the level of disorder taken into account in the simulation. Overall, our approach yields singlet diffusion lengths on the order of 10 nm as expected for energetically disordered molecular materials. |
| first_indexed | 2024-03-12T16:31:04Z |
| format | Article |
| id | doaj.art-044a968cbb6b4cabb17f90fb3ad0ecc7 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:31:04Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-044a968cbb6b4cabb17f90fb3ad0ecc72023-08-08T15:29:53ZengIOP PublishingNew Journal of Physics1367-26302020-01-0122303303310.1088/1367-2630/ab7a04Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theoryJens Wehner0Björn Baumeier1https://orcid.org/0000-0002-6077-0467Eindhoven University of Technology , Department of Mathematics and Computer Science & Institute for Complex Molecular Systems, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, GermanyEindhoven University of Technology , Department of Mathematics and Computer Science & Institute for Complex Molecular Systems, P.O. Box 513, 5600 MB Eindhoven, The NetherlandsWe present a multiscale model based on many-body Green’s functions theory in the GW approximation and the Bethe–Salpeter equation ( GW -BSE) for the simulation of singlet and triplet exciton transport in molecular materials. Dynamics of coupled electron–hole pairs are modeled as a sequence of incoherent tunneling and decay events in a disordered morphology obtained at room temperature from molecular dynamics. The ingredients of the rates associated to the events, i.e. reorganization energies, site energies, lifetimes, and coupling elements, are determined from a combination of GW -BSE and classical polarizable force field techniques. Kinetic Monte Carlo simulations are then employed to evaluate dynamical properties such as the excitonic diffusion tensor and diffusion lengths. Using DCV5T-Me(3,3), a crystalline organic semiconductor, we demonstrate how this multiscale approach provides insight into the fundamental factors driving the transport processes. Comparing the results obtained via different calculation models, we investigate in particular the effects of charge-transfer mediated high exciton coupling and the influence of internal site energy disorder due to conformational variations. We show that a small number of high coupling elements indicative of delocalized exciton states does not impact the overall dynamics perceptively. Molecules with energies in the tail of the excitonic density of states dominate singlet decay, independent of the level of disorder taken into account in the simulation. Overall, our approach yields singlet diffusion lengths on the order of 10 nm as expected for energetically disordered molecular materials.https://doi.org/10.1088/1367-2630/ab7a04multiscale modelingenergy transportGreen's functionsBethe–Salpeter equationmany-body electronic structure calculations |
| spellingShingle | Jens Wehner Björn Baumeier Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory New Journal of Physics multiscale modeling energy transport Green's functions Bethe–Salpeter equation many-body electronic structure calculations |
| title | Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory |
| title_full | Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory |
| title_fullStr | Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory |
| title_full_unstemmed | Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory |
| title_short | Multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many-body Green's functions theory |
| title_sort | multiscale simulations of singlet and triplet exciton dynamics in energetically disordered molecular systems based on many body green s functions theory |
| topic | multiscale modeling energy transport Green's functions Bethe–Salpeter equation many-body electronic structure calculations |
| url | https://doi.org/10.1088/1367-2630/ab7a04 |
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