Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, USA.
Department of Materials Science and Engineering and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, USA.
Nat Mater. 2021 Apr;20(4):525-532. doi: 10.1038/s41563-020-00872-6. Epub 2021 Jan 11.
Rapid increase in the power conversion efficiency of organic solar cells (OSCs) has been achieved with the development of non-fullerene small-molecule acceptors (NF-SMAs). Although the morphological stability of these NF-SMA devices critically affects their intrinsic lifetime, their fundamental intermolecular interactions and how they govern property-function relations and morphological stability of OSCs remain elusive. Here, we discover that the diffusion of an NF-SMA into the donor polymer exhibits Arrhenius behaviour and that the activation energy E scales linearly with the enthalpic interaction parameters χ between the polymer and the NF-SMA. Consequently, the thermodynamically most unstable, hypo-miscible systems (high χ) are the most kinetically stabilized. We relate the differences in E to measured and selectively simulated molecular self-interaction properties of the constituent materials and develop quantitative property-function relations that link thermal and mechanical characteristics of the NF-SMA and polymer to predict relative diffusion properties and thus morphological stability.
随着非富勒烯小分子受体（NF-SMAs）的发展，有机太阳能电池（OSCs）的功率转换效率得到了快速提高。尽管这些 NF-SMA 器件的形态稳定性对其内在寿命有至关重要的影响，但它们的基本分子间相互作用以及它们如何控制 OSCs 的性能-功能关系和形态稳定性仍然难以捉摸。在这里，我们发现 NF-SMA 向给体聚合物的扩散呈现出 Arrhenius 行为，并且活化能 E 与聚合物和 NF-SMA 之间的焓相互作用参数 χ 呈线性关系。因此，热力学上最不稳定、低混溶性的体系（高 χ）在动力学上最稳定。我们将 E 的差异与所测量的和有选择地模拟的组成材料的分子自相互作用特性相关联，并开发出定量的性能-功能关系，将 NF-SMA 和聚合物的热和力学特性联系起来，以预测相对扩散性能，从而预测形态稳定性。
