High‐Performance CsPbI<i><sub>x</sub></i>Br<sub>3‐</sub><i><sub>x</sub></i> All‐Inorganic Perovskite Solar Cells with Efficiency over 18% via Spontaneous Interfacial Manipulation
Yifan Zheng, Xiaoyu Yang, Rui Su, Pan Wu, Qihuang Gong, Rui Zhu
Abstract
Abstract Cesium‐based all‐inorganic halide perovskites solar cells (PSCs) have recently attracted increasing attention. Currently, due to the existence of high defects density and unoptimized interfacial morphology, “state‐of‐the‐art” performances of all‐inorganic PSCs are still far away from their theoretical limits. Although commonly used two‐step passivation methods can effectively passivate the perovskite surface, they will inevitably detriment the original perovskite morphology due to the use of weak‐polarity solvents. This will potentially result in the unintentional doping, uncontrollable interfacial band alignment, and the additional defects formation. Hence, a spontaneous interfacial manipulation (SIM) method is developed to self‐organize a 2D/3D multidimensional perovskite top interface. It is demonstrated that the spontaneously formed ultrathin 2D perovskite can not only eliminate the interfacial defects, but also effectively prevent moisture penetration. As a result, a significant power conversion efficiency enhancement from 13.64% to over 18% is obtained along with greatly extended device lifetime, for CsPbI x Br 3‐ x ‐based all‐inorganic PSC.