Pang Shangzheng, Zhang Chunfu, Dong Hang, Zhang Zeyang, Chen Dazheng, Zhu Weidong, Chang Jingjing, Lin Zhenhua, Zhang Jincheng, Hao Yue
Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, Shaanxi Joint Key Laboratory of Graphene, School of Microelectronics, Xidian University, Xi'an 710071, China.
ACS Appl Mater Interfaces. 2021 Mar 3;13(8):10110-10119. doi: 10.1021/acsami.1c00066. Epub 2021 Feb 19.
Perovskite film modification is one of the most effective methods to improve the performance of perovskite solar cells. The modification should follow its characters of an asymmetric structure and the corresponding charge transportation and extraction. In this work, it is shown that synchronous interface modification and bulk passivation for highly efficient PSCs can be achieved by a one-step cesium bromide (CsBr) diffusion process because it is more suitable for an asymmetric structure. The synchronous interface modification and bulk asymmetric passivation can be better applied to the asymmetric PSC structure and can boost the power conversion efficiency apparently from 19.5 to 22.1%. It is shown that the perovskite crystallization is improved and the charge extraction is also enhanced obviously due to the better band alignment matching. The diffusion of CsBr into the perovskite bulk could form a gradient distribution, which is more applicable to the asymmetric charge transport and extraction. Thus, the CsBr at the interface between the electronic transport layer (ETL) and perovskite, as well as in the perovskite bulk, could suppress charge recombination. All of these factors can improve the and as well as the power conversion efficiency (PCE) of the PSCs. The results point out that the studied method is a simple and efficient way to fabricate high-performance PSCs by interface modification and bulk asymmetric passivation in a single step.
钙钛矿薄膜修饰是提高钙钛矿太阳能电池性能最有效的方法之一。这种修饰应遵循其不对称结构以及相应的电荷传输和提取特性。在这项工作中，研究表明，通过一步溴化铯（CsBr）扩散过程可以实现高效钙钛矿太阳能电池的同步界面修饰和体相钝化，因为它更适合不对称结构。同步界面修饰和体相不对称钝化可以更好地应用于不对称钙钛矿太阳能电池结构，并能将功率转换效率从19.5%显著提高到22.1%。结果表明，由于更好的能带对准匹配，钙钛矿结晶得到改善，电荷提取也明显增强。CsBr扩散到钙钛矿体相中可形成梯度分布，这更适用于不对称电荷传输和提取。因此，电子传输层（ETL）与钙钛矿之间界面处以及钙钛矿体相中的CsBr可以抑制电荷复合。所有这些因素都可以提高钙钛矿太阳能电池的 和 以及功率转换效率（PCE）。结果指出，所研究的方法是一种通过一步界面修饰和体相不对称钝化来制备高性能钙钛矿太阳能电池的简单有效方法。
