Assessing the nature of the charge-transfer electronic states in organic solar cells
Assessing the nature of the charge-transfer electronic states in organic solar cells
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DOI：
10.1038/s41467-018-07707-8
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发表时间：
2018-12-13
影响因子：
16.6
通讯作者：
Bredas, Jean-Luc
中科院分区：
文献类型：
--
作者：
Chen, Xian-Kai;Coropceanu, Veaceslav;Bredas, Jean-Luc
在有机太阳能电池中，在供体-受体界面处出现的电荷转移电子态介导激子解离、电荷产生和电荷复合。迄今为止，其性质的表征已经进行了模型的基础上，只涉及电荷转移状态和基态。在这里，我们证明，它是必不可少的超越这样一个两态模型，并明确考虑电子和振动耦合与当地的吸收状态上的施主和/或受体。因此，我们发展了一个三态电子振动模型，它使我们能够可靠地描述与电荷转移态有关的光吸收特性，并指出了应用半经典两态模型所引起的错误解释;并使局部激发态和电荷转移态之间的杂化如何能够导致较低的非-辐射电压损耗和更高的功率转换效率。
The charge-transfer electronic states appearing at the donor-acceptor interfaces in organic solar cells mediate exciton dissociation, charge generation, and charge recombination. To date, the characterization of their nature has been carried out on the basis of models that only involve the charge-transfer state and the ground state. Here, we demonstrate that it is essential to go beyond such a two-state model and to consider explicitly as well the electronic and vibrational couplings with the local absorbing state on the donor and/or acceptor. We have thus developed a three-state vibronic model that allows us: to provide a reliable description of the optical absorption features related to the charge-transfer states; to underline the erroneous interpretations stemming from the application of the semi-classical two-state model; and to rationalize how the hybridization between the local-excitation state and charge-transfer state can lead to lower non-radiative voltage losses and higher power conversion efficiencies.