Synergistic Effect of Anti‐Solvent and Component Engineering for Effective Passivation to Attain Highly Stable Perovskite Solar Cells

Defect passivation is a crucial process for achieving high‐performance perovskite solar cells (PSCs). Herein, the synergistic effect of anti‐solvent and component engineering for effective passivation to attain highly stable PSCs is demonstrated, specifically, for ethyl acetate as the anti‐solvent and CsBr as the additive in the MAPbI3 precursor solution. It is found that the rapid solvent evaporation results in fast nucleation, and the CsBr assists the perovskite grain growth. The synergistic effect of anti‐solvent and additive engineering leads to increased perovskite grain size, reduced defect density, improved quality of the perovskite thin film, and finally, enhanced efficiency and stability of the indium tin oxide/SnO2/perovskite/carbon device. The influence of this synergistic effect on the morphology and photovoltaic performance is systematically investigated. Printable PSCs with hole‐transport‐layer‐free carbon electrodes are designed and constructed, which achieve a champion photoelectric conversion efficiency of 16.45%, fill factor of 72.63%, short circuit current of 19.90 mA cm−2, and open circuit voltage of 1.14 V. Herein, a facile and low‐cost approach is demonstrated to obtain highly stable C‐PSCs and a promising strategy for future commercial application is provided.