Key Laboratory of Novel Thin-Film Solar Cells, Institute of Applied Technology, Chinese Academy of Sciences, Hefei 230031, China.
State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China.
Nanoscale. 2017 Apr 6;9(14):4691-4699. doi: 10.1039/c6nr07689k.
Two-step deposition has been widely used in the perovskite layer preparation for perovskite solar cells due to its attractive morphology controllability. However, the limited diffusivity of CHNHI (MAI) might cause some PbI to remain in the perovskite film. The residual PbI in the perovskite film would lead to inferior performance of devices, such as, low power conversion efficiency (PCE), poor reproducibility and weak air stability. In this work, we developed a sandwich structure MAI-PbI-MAI precursor film to prepare a PbI-free CHNHPbI perovskite film. In comparison to the two-step approach, the MAI-PbI-MAI precursor film with a typical sandwich structure formed a uniform and pinhole-free perovskite film without any PbI residue, which could significantly improve the performance of the devices. Moreover, the bottom MAI layer of the MAI-PbI-MAI precursor film could improve the interfacial contact of the porous TiO layer, leading to the promotion of the charge transfer and reduction of the recombination rate. Therefore, the devices fabricated from the sandwich structure MAI-PbI-MAI precursor films showed dramatic improvements of open-circuit voltage (V), short-circuit current density (J), fill factor (FF) and PCE. As a result, a promising PCE of 17.8% with good long-term air stability was achieved for the MAI-PbI-MAI precursor film based PSC, which is better than that prepared by a two-step approach.
两步沉积由于其吸引人的形态可控性，已广泛应用于钙钛矿太阳能电池的钙钛矿层制备中。然而，CHNHI（MAI）的有限扩散性可能导致一些 PbI 残留在钙钛矿薄膜中。钙钛矿薄膜中的残留 PbI 会导致器件性能下降，例如，低功率转换效率（PCE）、较差的重现性和较弱的空气稳定性。在这项工作中，我们开发了一种三明治结构的 MAI-PbI-MAI 前驱体膜来制备无 PbI 的 CHNHPbI 钙钛矿薄膜。与两步法相比，具有典型三明治结构的 MAI-PbI-MAI 前驱体膜形成了均匀且无针孔的钙钛矿薄膜，没有任何 PbI 残留，这可以显著提高器件的性能。此外，MAI-PbI-MAI 前驱体膜的底部 MAI 层可以改善多孔 TiO 层的界面接触，从而促进电荷转移并降低复合速率。因此，基于三明治结构 MAI-PbI-MAI 前驱体膜制备的器件在开路电压（V）、短路电流密度（J）、填充因子（FF）和 PCE 方面都有显著提高。结果，基于 MAI-PbI-MAI 前驱体膜的 PSC 实现了 17.8%的有前途的 PCE 和良好的长期空气稳定性，优于两步法制备的 PSC。
