Charge Separation in Donor-C60 Complexes with Real-Time Green Functions : The Importance of Nonlocal Correlations
(2018) In Nano Letters 18(2). p.785-792- Abstract
We use the nonequilibrium Green function (NEGF) method to perform real-time simulations of the ultrafast electron dynamics of photoexcited donor-C60 complexes modeled by a Pariser-Parr-Pople Hamiltonian. The NEGF results are compared to mean-field Hartree-Fock (HF) calculations to disentangle the role of correlations. Initial benchmarking against numerically highly accurate time-dependent density matrix renormalization group calculations verifies the accuracy of NEGF. We then find that charge-transfer (CT) excitons partially decay into charge separated (CS) states if dynamical nonlocal correlation corrections are included. This CS process occurs in ∼10 fs after photoexcitation. In contrast, the probability of exciton... (More)
We use the nonequilibrium Green function (NEGF) method to perform real-time simulations of the ultrafast electron dynamics of photoexcited donor-C60 complexes modeled by a Pariser-Parr-Pople Hamiltonian. The NEGF results are compared to mean-field Hartree-Fock (HF) calculations to disentangle the role of correlations. Initial benchmarking against numerically highly accurate time-dependent density matrix renormalization group calculations verifies the accuracy of NEGF. We then find that charge-transfer (CT) excitons partially decay into charge separated (CS) states if dynamical nonlocal correlation corrections are included. This CS process occurs in ∼10 fs after photoexcitation. In contrast, the probability of exciton recombination is almost 100% in HF simulations. These results are largely unaffected by nuclear vibrations; the latter become however essential whenever level misalignment hinders the CT process. The robust nature of our findings indicates that ultrafast CS driven by correlation-induced decoherence may occur in many organic nanoscale systems, but it will only be correctly predicted by theoretical treatments that include time-nonlocal correlations.
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- author
- Boström, Emil Viñas LU ; Mikkelsen, Anders LU ; Verdozzi, Claudio LU ; Perfetto, Enrico and Stefanucci, Gianluca LU
- organization
- publishing date
- 2018-02-14
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Charge transfer, donor-acceptor complex, nonequilibrium Green functions, real-time simulations, ultrafast dynamics
- in
- Nano Letters
- volume
- 18
- issue
- 2
- pages
- 8 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- pmid:29266952
- scopus:85042127647
- ISSN
- 1530-6984
- DOI
- 10.1021/acs.nanolett.7b03995
- language
- English
- LU publication?
- yes
- id
- 5fb100bf-c5b7-4c60-9dfd-540584deed9a
- date added to LUP
- 2018-03-06 11:56:25
- date last changed
- 2024-06-24 10:55:30
@article{5fb100bf-c5b7-4c60-9dfd-540584deed9a, abstract = {{<p>We use the nonequilibrium Green function (NEGF) method to perform real-time simulations of the ultrafast electron dynamics of photoexcited donor-C<sub>60</sub> complexes modeled by a Pariser-Parr-Pople Hamiltonian. The NEGF results are compared to mean-field Hartree-Fock (HF) calculations to disentangle the role of correlations. Initial benchmarking against numerically highly accurate time-dependent density matrix renormalization group calculations verifies the accuracy of NEGF. We then find that charge-transfer (CT) excitons partially decay into charge separated (CS) states if dynamical nonlocal correlation corrections are included. This CS process occurs in ∼10 fs after photoexcitation. In contrast, the probability of exciton recombination is almost 100% in HF simulations. These results are largely unaffected by nuclear vibrations; the latter become however essential whenever level misalignment hinders the CT process. The robust nature of our findings indicates that ultrafast CS driven by correlation-induced decoherence may occur in many organic nanoscale systems, but it will only be correctly predicted by theoretical treatments that include time-nonlocal correlations.</p>}}, author = {{Boström, Emil Viñas and Mikkelsen, Anders and Verdozzi, Claudio and Perfetto, Enrico and Stefanucci, Gianluca}}, issn = {{1530-6984}}, keywords = {{Charge transfer; donor-acceptor complex; nonequilibrium Green functions; real-time simulations; ultrafast dynamics}}, language = {{eng}}, month = {{02}}, number = {{2}}, pages = {{785--792}}, publisher = {{The American Chemical Society (ACS)}}, series = {{Nano Letters}}, title = {{Charge Separation in Donor-C<sub>60</sub> Complexes with Real-Time Green Functions : The Importance of Nonlocal Correlations}}, url = {{http://dx.doi.org/10.1021/acs.nanolett.7b03995}}, doi = {{10.1021/acs.nanolett.7b03995}}, volume = {{18}}, year = {{2018}}, }