The Impact of Solvent Vapor on the Film Morphology and Crystallization Kinetics of Lead Halide Perovskites during Annealing.
The Impact of Solvent Vapor on the Film Morphology and Crystallization Kinetics of Lead Halide Perovskites during Annealing.
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DOI：
10.1021/acsami.1c09075
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发表时间：
2021-09
影响因子：
9.5
通讯作者：
Yu Zhong;D. Seeberger;E. Herzig;A. Köhler;Fabian Panzer;Cheng Li;S. Huettner
中科院分区：
文献类型：
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作者：
Yu Zhong;D. Seeberger;E. Herzig;A. Köhler;Fabian Panzer;Cheng Li;S. Huettner
在过去几年中，卤化物钙钛矿太阳能电池显著改进的关键因素之一是对钙钛矿结晶度及其薄膜形态的控制增加。在各种处理方法中，溶剂蒸气辅助退火（SVAA）已被证明在获得高质量钙钛矿薄膜方面具有前景。然而，对SVAA过程中钙钛矿结晶过程的全面了解仍然缺乏。在这项工作中，我们使用自制的设置来精确控制SVAA条件，以详细研究钙钛矿结晶动力学。通过在退火期间改变溶剂蒸气浓度，钙钛矿晶粒尺寸可以从200 nm调整到几微米。我们监测结晶动力学过程中的无溶剂退火和SVAA使用原位掠入射广角X射线散射，在那里我们发现一个减少的钙钛矿生长速率和低维钙钛矿的形成在SVAA过程中的钙钛矿层的顶部。最终薄膜的扫描电子显微镜图像进一步表明，在较高的溶剂浓度下，钙钛矿生长遵循奥斯特瓦尔德熟化过程。因此，我们的研究结果将有助于实现更有针对性的钙钛矿薄膜加工。
One of the key factors for the remarkable improvements of halide perovskite solar cells over the last few years is the increased control over perovskite crystallinity and its thin film morphology. Among various processing methods, solvent vapor-assisted annealing (SVAA) has proven to be promising in achieving high-quality perovskite films. However, a comprehensive understanding of the perovskite crystallization process during SVAA is still lacking. In this work, we use a home-built setup to precisely control the SVAA conditions to investigate in detail the perovskite crystallization kinetics. By changing the solvent vapor concentration during annealing, the perovskite grain size can be tuned from 200 nm to several micrometers. We monitor the crystallization kinetics during solvent-free annealing and SVAA using in situ grazing incidence wide-angle X-ray scattering, where we find a diminished perovskite growth rate and the formation of low dimensional perovskite at the top of the perovskite layer during SVAA. Scanning electron microscopy images of the final films further suggest that the perovskite growth follows an Ostwald ripening process at higher solvent concentrations. Thus, our results will contribute to achieve a more targeted processing of perovskite films.