Slot-die coating being compatible with the roll-to-roll technique has been regarded as a promising tool for upscaling the manufacturing of organic solar cells (OSCs). However, there has been a significant gap between the efficiencies of the state-of-the-art spin-coated devices and the scalable processed devices. The active layer morphology is crucial to achieve high efficiency in OSCs, which depends on the conditions of film fabrication. To figure out and optimize the slot-die coating process, a deeper understanding of the film formation kinetics is important. Herein, in situ measurements of the slot-die coating process based on the PM7:IT4F system are demonstrated to illustrate the aggregation and crystallization evolution at various die temperatures and substrate temperatures. OSCs with a high power conversion efficiency of 13.2% are achieved at 60 °C die temperature/60 °C substrate temperature due to the improved exciton dissociation, charge transport and suppressed non-radiative charge recombination. The optimized morphology is attributed to the balanced polymer pre-aggregation and small molecule crystallization kinetics. The unsuitable die temperature leads to overlarge phase separation and consequently inefficient exciton dissociation while the improper substrate temperature results in weak crystallization and the following shrunken carrier lifetime with strong non-radiative combination. This work provides fundamental understanding on the correlations among processing methodology, solution pre-aggregation, morphology formation kinetics, device physics and device performance and affords guidance for device optimization in scalable manufacturing.

中文翻译：

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平衡预聚集和结晶动力学，可实现高效的缝模涂布有机太阳能电池，并减少非辐射复合损失

与卷对卷技术兼容的狭缝模头涂层已被视为扩大有机太阳能电池（OSC）制造规模的有前途的工具。但是，最新的旋涂设备和可扩展处理设备的效率之间存在很大差距。有源层的形态对于在OSC中实现高效率至关重要，这取决于薄膜制造的条件。为了弄清楚并优化缝模涂布工艺，对成膜动力学的深入了解很重要。本文中，基于PM7的缝模涂布工艺的原位测量：IT4F系统被证明可以说明在各种芯片温度和基板温度下的聚集和结晶演变。由于改善了激子离解，电荷传输和抑制了非辐射电荷复合，在60°C的芯片温度/ 60°C的基板温度下获得了13.2％的高功率转换效率的OSC。优化的形态归因于平衡的聚合物预聚集和小分子结晶动力学。不合适的芯片温度会导致相分离过大，从而导致激子解离效率低下；而不合适的基板温度会导致结晶度降低，以及随后的载流子寿命缩短，以及强烈的非辐射结合。