Achieving 17.46% Efficiency CsPbI<sub>2</sub>Br Perovskite Solar Cells via Multifunction Lead Chloride‐Modified ZnO Electron Transporting Layer
Yaru Li, Yong Zhang, Peide Zhu, Jingbai Li, Jiawen Wu, Jiyao Zhang, Xianyong Zhou, Zhengyan Jiang, Xingzhu Wang, Baomin Xu
Abstract
Abstract CsPbI 2 Br perovskite solar cells (PSCs) have garnered significant attention owing to their remarkable thermal stability and desirable bandgap. However, CsPbI 2 Br‐based devices still face critical challenges, particularly at the interfaces between the active layer and adjacent components. In this study, a multifunctional ZnO composition has developed as the electron transporting layer (ETL) for CsPbI 2 Br PSCs, enabling simultaneous efficient charge extraction and passivation of buried interface defects in CsPbI 2 Br. The nanocomposite, composed of PbCl 2 ‐modified ZnO (PbCl 2 ‐ZnO), facilitates the regulation of bandgap and conduction band to align the energy level of ETL and CsPbI 2 Br. Additionally, the residual PbCl 2 at the buried interface of the perovskite incorporates into the perovskite lattice, reducing I defect and thus improving film quality. The improved energy level alignment at the ETL/CsPbI 2 Br interface and the suppressed I defect‐induced carrier nonradiative recombination result in a remarkable reduction in energy loss from 0.73 to 0.52 eV. Finally, the PbCl 2 ‐ZnO hybrid nanocomposite ETL significantly enhances the efficiency of CsPbI 2 Br PSCs, increasing it from 14.15% to 17.46%, representing one of the highest reported power conversion efficiency (PCE) values for CsPbI 2 Br PSCs. These findings demonstrate the potential of PbCl 2 ‐ZnO hybrid nanocomposite as an effective ETL for CsPbI 2 Br PSCs.