Accelerated Crystal Growth in >16% Printed MAxFAyCszPbI3 Perovskite Solar Cells from Aqueous Inks

A key to commercializing perovskite solar cells (PSCs) is to use less toxic solvents such as water, alcohol, and other nontoxic compounds when printing them. Improving the perovskite crystal growth rate to reduce defects produced by the Ostwald ripening effect is a critical challenge in fabricating high-quality perovskite films from aqueous inks. In this study, we reported an accelerated crystal growth strategy for printing MAxFAyCszPbI3 perovskite films with aqueous inks. The use of trace amounts of MAI in aqueous inks to generate nanosized PbI2 seeds increased the perovskite formation speed by about 30% and reduced the apparent activation energy of the perovskite forming reaction by about 700 J·mol–1. Consequently, printed PSCs achieved a power conversion efficiency (PCE) of 16.53% and showed an ameliorative stability of 400 h in a dry environment. We proved that high-performance PSCs can be fabricated using aqueous inks, which demonstrated that toxic solvents are not inevitable of fabricating high-performance PSCs.