How to Make 20% Efficient Perovskite Solar Cells in Ambient Air and Encapsulate Them for 500 h of Operational Stability

The performance of perovskite solar cells (PSCs) has seen rapid growth in the last decade due to the meticulous optimization of device fabrication procedures and material compositions. Most reports focus on device fabrication protocols in an inert atmosphere. Only a few offer reproducible methods to fabricate PSCs in ambient air, and even fewer report the stable maximum power point (MPP) operation of devices. This methods/protocol article presents detailed protocols for fabricating 20% milestone PSCs in ambient air and their encapsulation toward a stable 500+ h MPP operation. We also developed a simple encapsulation testing protocol: we found that if an encapsulated device withstands 120 °C heat stress for 5 min in ambient air, it likely withstands long-term MPP conditions.