Degradation mechanisms of perovskite solar cells under vacuum and one atmosphere of nitrogen
Degradation mechanisms of perovskite solar cells under vacuum and one atmosphere of nitrogen
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DOI：
10.1038/s41560-021-00912-8
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发表时间：
2021-10-01
期刊：
影响因子：
56.7
通讯作者：
Muller-Buschbaum, Peter
中科院分区：
文献类型：
--
作者：
Guo, Renjun;Han, Dan;Muller-Buschbaum, Peter
广泛的研究集中在提高钙钛矿太阳能电池的运行稳定性，但很少有调查的基本降解机制。在早期的工作中忽略的一个方面是运行过程中气氛对设备性能的影响。本文采用同步辐射的operando掠射x射线散射方法研究了真空和氮气气氛下钙钛矿太阳能电池的降解机制。与之前报道的观察结果不同，我们发现在真空条件下会发生光致相偏析、晶格收缩和形态变形。在氮气条件下，太阳能电池在运行过程中只出现晶格收缩，从而提高了器件的稳定性。氮下的不同行为归因于晶格畸变和相偏析的更大能量垒。最后，我们发现过量的PbI2迁移到钙钛矿和空穴传输层之间的界面会降低器件在真空或氮气下的性能。了解钙钛矿太阳能电池的降解机制是其发展的关键。现在，Guo等人表明，在真空下操作的钙钛矿结构和形态比在氮气下操作的设备更容易降解。
Extensive studies have focused on improving the operational stability of perovskite solar cells, but few have surveyed the fundamental degradation mechanisms. One aspect overlooked in earlier works is the effect of the atmosphere on device performance during operation. Here we investigate the degradation mechanisms of perovskite solar cells operated under vacuum and under a nitrogen atmosphere using synchrotron radiation-based operando grazing-incidence X-ray scattering methods. Unlike the observations described in previous reports, we find that light-induced phase segregation, lattice shrinkage and morphology deformation occur under vacuum. Under nitrogen, only lattice shrinkage appears during the operation of solar cells, resulting in better device stability. The different behaviour under nitrogen is attributed to a larger energy barrier for lattice distortion and phase segregation. Finally, we find that the migration of excessive PbI2 to the interface between the perovskite and the hole transport layer degrades the performance of devices under vacuum or under nitrogen.Understanding degradation mechanisms in perovskite solar cells is key to their development. Now, Guo et al. show a greater degradation of the perovskite structure and morphology for devices operated under vacuum than under nitrogen.