Scalable Passivation Strategies to Improve Efficiency of Slot Die-Coated Perovskite Solar Cells

The power conversion efficiency (PCE) of spin-coated, ≪1 cm2, perovskite solar cells has exceeded 25%. The PCEs of the large-area perovskite solar cells made by scalable deposition techniques, however, are typically lower. One frequent element to improving performance in perovskites has been the utilization of nonscalable and low materials utilization, spin-based passivation treatments to reduce traps and defects in perovskite thin film absorber layers. Herein, we report a more sustainable passivation technique for large-area perovskite films via subsequent linear slot-die coating of a benzylammonium iodide (BAI) passivant formulation on the surface of previously deposited perovskite absorber layers. The BAI-passivated perovskite films demonstrate apparent larger grain size, higher photoluminescence (PL) intensity, reduced recombination rates as evidenced by longer PL lifetimes, and better spatial PL uniformity. The champion cell with optimized slot-die BAI passivation exhibited an improved PCE of ∼20.3%, as compared to 18.7% for the control device.