Quantum Master Equation Approach to Singlet Fission Dynamics in Pentacene Linear Aggregate Models: Size Dependences of Excitonic Coupling Effects
Quantum Master Equation Approach to Singlet Fission Dynamics in Pentacene Linear Aggregate Models: Size Dependences of Excitonic Coupling Effects
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DOI：
10.1002/jcc.25539
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发表时间：
2018-09
影响因子：
3
通讯作者：
M. Nakano;T. Nagami;Takayoshi Tonami;K. Okada;S. Ito;R. Kishi;Y. Kitagawa;T. Kubo
中科院分区：
文献类型：
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作者：
M. Nakano;T. Nagami;Takayoshi Tonami;K. Okada;S. Ito;R. Kishi;Y. Kitagawa;T. Kubo
利用量子主方程方法研究了并五苯线性聚合体模型的单线态裂变动力学，重点研究了Frenkel激子（FE）耦合对裂变速率和双三重态（TT）产率的影响以及它们对聚合体大小的依赖关系。研究发现，对于二聚体模型，需要不切实际的大有限元耦合才能对SF动力学产生显著影响，而对于较大的骨料模型，实际的有限元耦合会导致SF动力学发生显著变化。随着团聚体粒径的增加，SF率迅速增加，在8 - mer时达到最大值（与非FE -耦合情况相比增加了约3倍），然后下降，在12 - mer后接近平稳值，尽管20 - mer时的平稳TT产率仍略低于非FE -耦合情况。这些特征是基于绝热激子态之间的相对松弛因子来解释的。本文的研究结果有助于构建高效SF骨料的设计准则。©2018 Wiley期刊公司
The singlet fission (SF) dynamics of pentacene linear aggregate models are investigated using the quantum master equation method by focusing on the Frenkel excitonic (FE) coupling effects on the SF rate and double triplet (TT) yield as well as on their aggregate size dependences. It is found that for the dimer model, unrealistically large FE couplings are needed to provide significant effects on the SF dynamics, while for the larger aggregate models a realistic FE coupling causes significant variations in the SF dynamics: as increasing the aggregate size, the SF rate rapidly increases, attains the maximum at 8‐mer (~3 times enhancement as compared to the non‐FE‐coupling case) and then decreases, approaching a stationary value after 12‐mer, although the stationary TT yield at 20‐mer remains slightly smaller than that in the non‐FE‐coupling case. These features are explained based on the relative relaxation factors between the adiabatic exciton states. The present results contribute to constructing the design guidelines for highly efficient SF aggregates. © 2018 Wiley Periodicals, Inc.