High-performance Ruddlesden-Popper two-dimensional perovskite solar cells using integrated electron transport materials of tin oxide and indacenodithiophene

Perovskite solar cells (PSCs) have been rapidly developed and exhibit comparable power conversion efficiency (PCE) to silicon solar cells. However, the stability of PSCs needs to be further enhanced to satisfy the requirement of commercialization. As a result, Ruddlesden-Popper (RP) type two-dimensional (2D) perovskites with high intrinsic stability have been intensively studied. In this work, we improved the performance of RP-type 2D PSCs using tin oxide (SnO2) and indacenodithiophene (IDIC) as an integrated electron transport layer (ETL). Here, IDIC is used to tune the energy alignment and hydrophobicity of SnO2, which further improves the electron transport properties and film quality of perovskite. With the deposition of 15 nm IDIC on SnO2, the average PCE of the 2D PSCs was significantly improved from 11.7% to 14.8%, with simultaneously enhanced short-circuit current density and fill factor. The long-term stability of the studied 2D PSCs also improved with the PCE degradation significantly suppressed from 24.8% to 16.2% after a duration of 20 days. The best PSC with the integrated ETL of SnO2/IDIC exhibited a high PCE of 15.2%, with stable power output and negligible hysteresis. Our results demonstrate a simple and effective method for improving the performance of RP PSCs.