Synergistic enhancement of efficiency and stability in CsPbBr3 solar cells via a multifunctional PbCl2–ZnO electron transport

The electron transport layer (ETL) is critical in hole-transport-layer-free all-inorganic perovskite solar cells (PSCs). Although ZnO as an ETL exhibits high electron mobility and suitable energy levels, its high surface defect density often leads to interfacial recombination losses. In this study, PbCl 2 was incorporated into the ZnO ETL to passivate interfacial defects and optimize the energy level alignment. PSCs with a structure of FTO/PbCl 2 –ZnO/CsPbBr 3 /Carbon were fabricated. The resulting carbon-based CsPbBr 3 solar cells achieved a power conversion efficiency (PCE) of 7.0%, representing a 40% improvement over devices based on the pristine ZnO ETL. Furthermore, the unencapsulated devices retained 95% of their initial PCE after 60 days of storage under ambient conditions.