Charge Separation in Donor-C60 Complexes with Real-Time Green Functions: The Importance of Nonlocal Correlations
Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift
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.
|Enheter & grupper|
Ämnesklassifikation (UKÄ) – OBLIGATORISK
|Status||Published - 2018 feb 14|
|Peer review utförd||Ja|
Forskningsoutput: Avhandling › Doktorsavhandling (sammanläggning)