Achieving 17.46% Efficiency CsPbI2Br Perovskite Solar Cells via Multifunction Lead Chloride‐Modified ZnO Electron Transporting Layer

Abstract

AbstractCsPbI2Br perovskite solar cells (PSCs) have garnered significant attention owing to their remarkable thermal stability and desirable bandgap. However, CsPbI2Br‐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 CsPbI2Br PSCs, enabling simultaneous efficient charge extraction and passivation of buried interface defects in CsPbI2Br. The nanocomposite, composed of PbCl2‐modified ZnO (PbCl2‐ZnO), facilitates the regulation of bandgap and conduction band to align the energy level of ETL and CsPbI2Br. Additionally, the residual PbCl2 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/CsPbI2Br 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 PbCl2‐ZnO hybrid nanocomposite ETL significantly enhances the efficiency of CsPbI2Br PSCs, increasing it from 14.15% to 17.46%, representing one of the highest reported power conversion efficiency (PCE) values for CsPbI2Br PSCs. These findings demonstrate the potential of PbCl2‐ZnO hybrid nanocomposite as an effective ETL for CsPbI2Br PSCs.