Kot M, Kegelmann L, Köbler H, Vorokhta M, Escudero C, Kúš P, Šmíd B, Tallarida M, Albrecht S, Abate A, Matolínová I, Schmeißer D, Flege J I
Applied Physics and Sensors, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Wachsmann-Allee 17, 03046, Cottbus, Germany.
Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Zuse-Strasse 1, 03046, Cottbus, Germany.
ChemSusChem. 2020 Nov 6;13(21):5722-5730. doi: 10.1002/cssc.202001527. Epub 2020 Sep 15.
For several years, scientists have been trying to understand the mechanisms that reduce the long-term stability of perovskite solar cells. In this work, we examined the effect of water and photon flux on the stability of CH NH PbI perovskite films and solar cells using in situ near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), field emission scanning electron microscopy (FESEM), and current density-voltage (J-V) characterization. The used amount of water vapor (up to 1 mbar) had a negligible impact on the perovskite film. The higher the photon flux, the more prominent were the changes in the NAP-XPS and FESEM data; also, a faster decline in power conversion efficiency (PCE) and a more substantial hysteresis in the J-V characteristics were observed. Based on our results, it can be concluded that the PCE decrease originates from the creation of Frenkel pair defects in the perovskite film under illumination. The stronger the illumination, the higher the number of Frenkel defects, leading to a faster PCE decline and more substantial hysteresis in the J-V sweeps.
多年来，科学家们一直在试图弄清楚降低钙钛矿太阳能电池长期稳定性的机制。在这项工作中，我们使用原位近常压X射线光电子能谱（NAP-XPS）、场发射扫描电子显微镜（FESEM）和电流密度-电压（J-V）表征，研究了水和光子通量对CH₃NH₃PbI₃钙钛矿薄膜及太阳能电池稳定性的影响。所用水蒸气量（高达1毫巴）对钙钛矿薄膜的影响可忽略不计。光子通量越高，NAP-XPS和FESEM数据中的变化就越显著；此外，还观察到功率转换效率（PCE）下降更快，以及J-V特性中的滞后现象更明显。基于我们的结果，可以得出结论，PCE下降源于光照下钙钛矿薄膜中弗伦克尔对缺陷的产生。光照越强，弗伦克尔缺陷数量越多，导致PCE下降更快，J-V扫描中的滞后现象更明显。
