Implementing a Two‐in‐One Defect Passivation Strategy Utilizing CsX for High‐Performance Printable Carbon‐Based Perovskite Solar Cells
Jingshan He, Jingwen He, Dun Ma, Wu Shao, Jie Sheng, Huidong Zhang, Liming Zhang, Can Zou, Tian Ding, Ronghao Cen, Shuang Yang, Qi Chen, Yongzhen Wu, Wenjun Wu, Weihong Zhu
Abstract
Abstract In the rapidly advancing realm of perovskite solar cells, the rectification of defects has surfaced as a crucial scientific challenge. The control over defect states, especially in printable mesoscopic perovskite solar cells (p‐MPSCs), is hindered by the complexities of screen‐printing technology. Here a novel “two‐in‐one” defect passivation strategy is presented, through doping TiO 2 paste with cesium halide salts (CsX, where X = F, Cl, Br, I) to integrate all‐inorganic Cs halides, particularly CsF, into the electron transport layer in p‐MPSCs. Owing to the robust interaction between F − ions and TiO 2 compared to Cs + ions, and the inability of F − to infiltrate the perovskite lattice, F − and Cs + play distinct roles starting from the buried interface of the p‐MPSCs. Specifically, F − can rectify the oxygen vacancies on the TiO 2 surface, thus alleviating the residual stress at the perovskite's buried interface. Simultaneously, Cs + diffuses to the top perovskite and mends the methylamine vacancies. As a result, the PCE of the optimal device, based on F‐doped TiO 2 , witnesses a significant improvement from 16.18% (control) to 18.24%. The two‐in‐one strategy utilizing CsX from the buried interface can well realize the all‐inorganic defect rectification, thereby offering a promising prospect for the enhancement of p‐MPSC performance.