Coherent Real-Space Charge Transport Across a Donor-Acceptor Interface Mediated by Vibronic Couplings.
Coherent Real-Space Charge Transport Across a Donor-Acceptor Interface Mediated by Vibronic Couplings.
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振动耦合介导的施主-受主界面相干实空间电荷输运。
DOI：
10.1021/acs.nanolett.9b03194
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发表时间：
2019-11
期刊：
影响因子：
10.8
通讯作者：
Ziyao Xu;Yi Zhou;Lynn Groß;Antonietta De Sio;C. Yam;C. Lienau;T. Frauenheim;Guanhua Chen
中科院分区：
文献类型：
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作者：
Ziyao Xu;Yi Zhou;Lynn Groß;Antonietta De Sio;C. Yam;C. Lienau;T. Frauenheim;Guanhua Chen
越来越多的实验和理论证据表明，电子自由度和核自由度之间的振动耦合在有机供体-受体杂化体的超快激发态动力学中起着重要作用。尽管振动耦合已被证明支持供体-受体界面上的电荷分离，但迄今为止，人们对其在此类系统中电荷的实空间传输中的作用知之甚少。本文利用时间依赖密度泛函紧密结合理论，结合开放系统的Ehrenfest分子动力学，从理论上研究了噻吩-富勒烯堆叠中的电荷输运。我们的研究结果揭示了相邻供体位点之间电荷密度的相干振荡，持续约200fs，并促进了聚合物堆栈内的电荷传输。在施主-受主界面处，振动波包被发射，在超过3nm的距离上相干地传播到受主区域。这支持了以前在有机光伏系统中远程弹道载流子运动的实验观察，并突出了振动耦合工程作为定制混合有机器件功能的概念的重要性。
There is growing experimental and theoretical evidence that vibronic couplings, couplings between electronic and nuclear degrees of freedom, play a fundamental role in ultrafast excited-state dynamics in organic donor-acceptor hybrids. Whereas vibronic coupling has been shown to support charge separation at donor-acceptor interfaces, so far, little is known about its role in the real-space transport of charges in such systems. Here we theoretically study charge transport in thiophene:fullerene stacks using time-dependent density functional tight-binding theory combined with Ehrenfest molecular dynamics for open systems. Our results reveal coherent oscillations of the charge density between neighboring donor sites, persisting for ∼200 fs and promoting charge transport within the polymer stacks. At the donor-acceptor interface, vibronic wave packets are launched, propagating coherently over distances of more than 3 nm into the acceptor region. This supports previous experimental observations of long-range ballistic charge-carrier motion in organic photovoltaic systems and highlights the importance of vibronic coupling engineering as a concept for tailoring the functionality of hybrid organic devices.