Perovskite Solar Cell Performance Boosted by Regulating the Ion Migration and Charge Transport Dynamics via Dual-Interface Modification of Electron Transport Layer

Abstract

Engineering the buried interfaces of perovskite solar cells (PSCs) is crucial for optimizing the device performance. We herein report a novel strategy by modifying the ETL−FTO interface with MgO, as well as the interface between the perovskite layer (PVKL) and the SnO 2 electron transfer layer (ETL) with formamidine bromide (FABr). The dual-interface ETL engineering substantially improved the photoelectric conversion efficiency (19.62 → 22.04%) and suppressed the hysteresis index (14.98 → 1.09%). The structure−activity relationship was explored by using transient photoelectric and time-offlight secondary-ion mass spectroscopic analyses. It was found that the FABr treatment enhanced the PVKL crystallinity and the PVKL−ETL interaction and that the MgO modification dramatically retarded the ion migration, which together optimized the ETL function. The mechanism underlying the influence of ion distribution on the dynamics of ions and free carriers is discussed, which may be helpful for the rational design of highperformance PSCs.

Inhibiting perovskite decomposition by a creeper-inspired strategy enables efficient and stable perovskite solar cells

“…In addition, the open-circuit voltage decay (OCVD) characteristics of the PSCs were measured to evaluate charge reorganization associated with ion mobility (Fig. 5f ) 46 , 47 . The fast decay can be ascribed to the free charge-induced recombination, while the slow decay is attributed to the ion accumulation-related charge recombination.…”