Surface Engineering and Growth Control for High-Performance Perovskite-Based Tandem Solar Cells

Organic-inorganic hybrid halide perovskites have attracted significant R&D attention in the photovoltaic (PV) community as a competitive technology for future PV applications. The certified efficiency of single-junction perovskite solar cell (PSC) has reached over 26%. In addition to single-junction PV applications, perovskites are also attractive for developing efficient dual-junction tandem solar cells. By tuning perovskite compositions, the optical bandgaps of perovskites can be adjusted over a wide range (e.g., 1.2 eV to 1.8 eV) with demonstrated high efficiency levels (e.g., >20%), making perovskites suitable for a variety of tandem configurations. In this talk, I will discuss our recent progress on suppressing defects in perovskites with a wide range of perovskite compositions. I will present a few strategies on surface engineering and growth control to improve device stability under operational conditions. These strategies are effective for suppressing defect formation, improving bulk and surface morphology, and minimizing ion migration in mixed halide perovskites. The physical and optoelectronic properties of perovskites can be affected by controlling the precursor chemistry and growth conditions. In addition, I will discuss our recent progress toward understanding the link between indoor and outdoor PSC degradation behaviours. To push perovskite PV toward commercialization, it is critical to understand device reliability under real-world outdoor conditions where multiple stress factors (e.g., light, heat, humidity) coexist. Understanding the link between indoor and outdoor behaviors is necessary to help identify accelerated indoor testing protocols to quickly guide perovskite PV development.