Transient Carrier Transport and Extraction in Passivated Perovskite Films

The efficiency of perovskite solar cells keeps improving owing to the development of versatile passivation strategies for defects formed during the preparation of the films. Understanding the specific role of the passivation effect is a key step toward reaching the Shockley–Queisser limit. In this report, we focus on sun-like low excitation intensities to probe the carrier dynamics with passivation, as well as the charge transfer dynamics at the interface between the perovskite and the charge transport layer (CTL). The addition of the passivation layer reduces the density of both shallow and deep defects in the perovskite film, increases the carrier lifetime, enhances the diffusion coefficient and diffusion length, and accelerates carrier extraction at the interface. The imbalance of electron and hole extraction under passivation was also analyzed. These findings have direct implications for understanding the passivation effect and improving the efficiency of perovskite solar cells.