Enhanced Performance of Carbon‐Based, Fully Printed Mesoscopic Perovskite Solar Cells through Defects Passivation

Abstract Carbon‐based, fully printed mesoscopic perovskite solar cells (PMPSCs) possess outstanding environmental stability, which can be fabricated by screen‐printing techniques with low costs in large area. The performance of PMPSCs is severely hindered by strong carrier recombination from ionic defects at the grain boundaries in perovskite films. In this work, ethylene carbonate (EC) with electron‐rich CO functional groups are successfully introduced in to (5‐AVA) x MA 1− x PbI 3 PMPSCs as an additive to effectively suppress carrier recombination by passivating the defects at grain boundaries. The density functional theory calculations and film characterization reveal that EC effectively reduces charge trapping density by passivation of defects. With the introduction of EC, the power conversion efficiency (PCE) of PMPSCs with EC is increased up to 15.28% from 12.99% of PMPSCs without EC. In addition, PMPSCs with EC show excellent stability and better moisture resistance under air conditions. The PMPSCs with EC keep above 90% of the original PCE after 55 days stored in air with a humidity of 60 ± 10%. The work offers a strategy to passivate defects in high‐performance PMPSCs with excellent stability.