Achieving both high efficiency and stability is essential for the commercial applications of organic photovoltaics (OPVs). However, the molecular diffusion behaviour of small molecule acceptors (SMAs) under light or thermal stress is detrimental to device stability. Herein, we developed two butterfly-shaped non-fused ring electron acceptors (NFREAs), X7-D and X8-D, featuring four outstretched terminal groups that are fluorinated in X7-D and chlorinated in X8-D, aimed at developing thermodynamically stable systems. These NFREAs were subsequently incorporated as the third component into the D18:Y6-based binary OPV for higher efficiency and better stability. Based on this system, the molecular diffusion model was quantitatively resolved, establishing a correlation between the diffusion coefficient and thermal characteristics, expressed by the equation D₈₅ = 5.7 × 10⁸e^(−0.15T_g). The fluorinated X7-D not only serves as an effective morphology stabilizer, suppressing molecular diffusion to maintain a robust morphology, but also facilitates faster charge separation and enhances intermolecular interactions for efficient charge transport. Consequently, the efficiency increased to 18.80%, accompanied by improved photo stability and thermal stability in D18:Y6:X7-D-based ternary OPVs. Our work underscores the potential of butterfly-shaped NFREAs in achieving high-performance and stable OPVs. Additionally, it provides invaluable insights into prescreening the stability of emerging materials through simple thermal characteristics, thus holding great promise for accelerating the development of cost-effective and durable OPV technologies.

中文翻译：

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解析基于蝶形非熔融环形电子受体的分子扩散模型，用于稳定性更高的高效三元有机光伏


实现高效率和稳定性对于有机光伏 （OPV） 的商业应用至关重要。然而，小分子受体 （SMA） 在光或热应力下的分子扩散行为不利于器件稳定性。在此，我们开发了两个蝴蝶形非熔融环形电子受体 （NFREA），X7-D 和 X8-D，具有四个伸出的末端基团，在 X7-D 中被氟化，在 X8-D 中被氯化，旨在开发热力学稳定的系统。这些 NFREA 随后作为第三个组件掺入基于 D18：Y6 的二元 OPV 中，以实现更高的效率和更好的稳定性。基于该系统，对分子扩散模型进行了定量解析，建立了扩散系数和热特性之间的相关性，用方程式 D₈₅ = 5.7 × 10⁸e^{（−0.15T_g）} 表示.氟化 X7-D 不仅是一种有效的形态稳定剂，抑制分子扩散以保持稳健的形态，还有助于更快的电荷分离并增强分子间相互作用，以实现高效的电荷传输。因此，在 D18：Y6：X7-D 基三元 OPV 中，效率提高到 18.80%，同时光稳定性和热稳定性也有所提高。我们的工作强调了蝴蝶形 NFREA 在实现高性能和稳定的 OPV 方面的潜力。此外，它还为通过简单的热特性预筛选新兴材料的稳定性提供了宝贵的见解，从而为加速开发具有成本效益和耐用的 OPV 技术带来了巨大的希望。