强剪切流刷涂制备有机太阳能电池

有机太阳能电池具有可通过溶液法处理、兼容卷对卷生产工艺、便于制备柔性器件的特点，成为近年来新能源领域的研究热点。当前单结有机太阳能电池功率转换效率（PCE）已超过18%，已达到商业化应用的门槛。但距离产业化生产仍有一段距离，主要因为：器件活性层形貌可控性和重复性不理想；缺乏兼顾器件效率和大面积生产工艺过程的有机半导体薄膜制备方法。

本文提出了一种新颖的柔性微梳刷涂方法，该方法加强了溶液法制备薄膜过程中的剪切流和拉伸流，消除了当前大面积生产工艺的弊端，实现了活性层形貌的稳定控制和优于标准旋涂器件的性能。引入了Landau-Levich模型和液膜找平模型，并根据实验结果对模型进行修正，发现了柔性微梳刷涂薄膜制备过程的找平规律。通过Star-CCM模拟刷涂过程，得到了刷涂时梳齿附近剪切率和拉伸应变速率分布，并证实了溶液找平过程与液膜状态的关系。在研究微梳刷涂流体力学过程的基础上，分别制备了有机太阳能电池的空穴传输层、活性层和电子传输层，并实现了全刷涂方法制备有机太阳能电池器件。对比了刷涂与旋涂方法在薄膜形貌和器件光电性能方面的差异，结果证明刷涂法可显著提高薄膜结晶度，诱导给受体形成合适域尺寸的相分离形貌，从而实现刷涂器件光电转换效率（PCE=15.93%）优于旋涂器件（PCE=15.37%）。此外，微梳刷片的柔性使得刷片可直接与基底接触，便于在柔软或弯曲的基材上制备器件。本研究通过微梳刷涂方法制备的柔性器件PCE达到13.62%，是当前报道的非旋涂工艺制备柔性器件最高效率之一。这些结果证明柔性微梳刷涂是一种制备高性能有机太阳能电池的可靠方法。

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