Fabrication of p–i–n Structured Perovskite Solar Cells: Strategies for >20% Efficiency in Ambient Air, Encapsulation for Water, and 1000 h of Operational Stability

Organic–inorganic hybrid perovskite solar cells (PSCs) have recently gained considerable attention because of their excellent power conversion efficiency (PCE), which continuously increases, depending on the growth of the perovskite layer, material composition, and fabrication processes. However, the poor stability of the carrier transport and photoactive perovskite layer has so far been prevented, and stability has improved continuously. Most articles focused on inert atmosphere device fabrication, and only a few reported reproducible methods for fabricating stable PSCs in ambient air. This article presents easy protocols for the fabrication of PSCs with SAM, SAM/Al2O3, and NiOx/SAM/Al2O3 as the hole transport layer (HTL), and C60 and C60/AZO as the electron transport layer (ETL) in p–i–n device configurations in ambient air. We also developed a simple encapsulation strategy and found that the encapsulated device exhibits excellent ambient stability. In this work, our aim is to provide detailed strategies for deposition of high-quality perovskite films and good interfaces under ambient condition, which would yield highly efficient (>20%) PSCs in ambient air. These fabrication strategies of the PSCs in p–i–n configuration would definitely help to develop easy fabrication of silicon-perovskite tandem devices in the near future. This transparent reporting with all details of fabrication will also enable easier replication by other research group. In this study, after fabricating all the devices, we found the best-performing devices with a device structure of ITO/NiOx/SAM/Al2O3/perovskite/C60/AZO/BCP/Ag, which yielded 20.83% PCE and showed more than 10,000 h long-term stability, maintaining 95% of initial PCE.