Interfacial Modification of Perovskite Solar Cells Using an Ultrathin MAI Layer Leads to Enhanced Energy Level Alignment, Efficiencies, and Reproducibility

. It is not the MAI layer but the dissociated species that leads to the interfacial energy-level tuning. Optimized interface energetics were verified by solar cell device testing, leading to both an increase of 19% in average steady-state power conversion efficiency (PCE) and significantly improved reproducibility, which is represented by a much lower PCE standard deviation (from 15 ± 2% to 17.2 ± 0.4%).