(Invited) Towards Outdoor Operation of Perovskite Solar Cells

Organic-inorganic hybrid halide perovskites represent a new class of light absorbers that have demonstrated multiple ideal characteristics and a rapid performance progress for solar conversion applications. Perovskite-based photovoltaic (PV) technologies have attracted significant R&D attention in the PV community as a promising next-generation approach for future PV applications. The certified efficiency of single-junction perovskite solar cells (PSCs) has reached greater than 26%. In order to reach the commercialization stage for perovskite PV, significant efforts are still needed to demonstrate the robust operation under real-world condition for multiple decades. To speed up this process, it is important to develop accelerated aging test protocols and understand their correlation to device operation under outdoor conditions. Here, I will first present our recent studies on perovskite surface engineering to improve device stability under indoor operational conditions. Using molecules/structures based on bulky organic cations (e.g., phenethylammonium) to improve the surface or interface properties is promising for improving PSC performance. A few strategies on suppressing defect formation, improving bulk and surface morphology, and reducing transport barriers for better extraction will be highlighted. In the second part of presentation, I will discuss our recent progress toward understanding the correlation between indoor and outdoor PSC degradation behaviours. Understanding device reliability under real-world outdoor conditions where multiple stress factors (e.g., light, heat, humidity) coexist is critical to moving perovskite PV toward commercialization. It is important to understand the link between indoor and outdoor behaviors in order to help identify accelerated indoor testing protocols to quickly guide PSC development.