Revisiting Crystal Growth and Composition Engineering for Reproducible Fabrication of High-Performance Perovskite Solar Cells

Metal halide perovskite solar cells (PSCs) have been spotlighted as a promising next-generation photovoltaic technology. Recently, there has been a surge of efforts in the commercialization of PSCs in academia and industries worldwide with record power conversion efficiencies over 26% for both n-i-p and p-i-n structured devices. Nevertheless, their subpar operational durability, module scalability, and material toxicity are challenges often brought up as the major barriers hindering practical commercialization. The poor reproducibility of PSCs has been relatively overlooked, but negatively impacts institutional research laboratories, start-up companies, and large established corporations all alike. Reproducible fabrication of PSCs is a critical consideration for market viability and practical commercialization. In this work, I will discuss the critical functions of atmospheric humidity to regulate the crystallization and stabilization of formamidinium lead triiodide (FAPbI₃) perovskites. We demonstrate that the humidity content during processing underlies profound variations in perovskite stoichiometry, thermodynamic stability, optoelectronic quality and thus reproducibility of PSCs. In second part of the presentation, I will discuss the interplay between composition of perovskite, and performance and stability of inverted PSCs. We rationalize the difference in widely used perovskite compositions in n-i-p and p-i-n PSCs.