Figure 1.

J–V curves of champion MAPbI₃ solar cells made using the low-purity MAI (a) or the high-purity MAI (b). For the low-purity MAI, the champion power conversion efficiency (PCE) was 14.4% and the stabilized power output (SPO) was 15.7%. For the high-purity MAI, the champion PCE was 15.0% and the SPO was 15.3%. During the evaporation runs, the quartz microbalance (QMB) rate and the MAI source temperature (c, d) were measured. Additionally, a residual gas analysis (RGA) system was used to track selected mass spectroscopy peaks (e, f) over the course of the respective evaporation run.