Hybrid Inorganic Electron-Transporting Layer Coupled with a Halogen-Resistant Electrode in CsPbI2Br-Based Perovskite Solar Cells to Achieve Robust Long-Term Stability.

Along with the rapidly developed power conversion efficiencies (PCEs), operational stability of perovskite solar cells (PSCs) remains a bottleneck for further commercialization. The instability mainly arises from the unstable organic components in the whole devices and the responsive metal electrode to the halogens from perovskites. In this work, we develop a carbide-titanium oxide (C-TiO2) hybrid electron-transporting layer (ETL) and a halogen-resistant Sb electrode on top of the inorganic CsPbI2Br layer to solve the issues of instability. The hybrid C-TiO2 presents a uniform and pinhole-free morphology, adequate band structure and electronic property, and observably strong stability. On the other hand, Sb is demonstrated to be effective to restrict inferior ion diffusion and further perovskite decomposition. As a result, our well-designed PSCs achieve both high efficiencies (14.8% for the champion device) and long-term stabilities (<6% decline @ 85 °C, dark, <10% decline @ 60 °C, continuous illumination) of 1000 h.