Аңдатпа
In this work, we have studied the effects of the compact TiO2(c-TiO2) and mesoscopic TiO2(mp-TiO2) layers on the performance of the perovskite based solar cells (PSCs). It is found that the increased interfacial area between the mesoscopic electron transport layer (ETL) and perovskite can enhance the device efficiency, particularly for the fill factor. We have then synthesized TiO2nanorods (TiO2-NR) and incorporated it into PSCs, in which the interfacial area between perovskite and TiO2-NA is further increased. A hysteresis-free PSC with the power conversion efficiency (PCE) of 19 % can be obtained by using TiO2-NR as the ETL. The results of femtosecond transient absorption (fs-TA) clearly show that the carrier extraction efficiency is significantly enhanced due to substantial increase of the interfacial area between the perovskite and ETL nanostructures, resulting in a reduction in carrier diffusion distance.