5-Chloroindole as Interface Modifier to Improve the Efficiency and Stability of Planar Perovskite Solar Cells

Interface engineering has been proven to be an effective method to improve the performance and stability of perovskite solar cells (PSCs). Herein, 5-chloroindole (Cl-indole) is introduced into the interface of a SnO 2 electron transport layer and perovskite light-absorbing layer to improve the photovoltage performance of the device. The results show that Cl−indole can not only form hydrogen bonds with iodine in the perovskite to optimize the interface contact but also coordinate and passivate the Pb 2+ and Sn 4+ interface defects to alleviate carrier nonradiative recombination. Compared with the pristine SnO 2 -based planar PSCs with a power conversion efficiency (PCE) of 20.58%, the Cl−indole-modified SnO 2 -based device achieves a PCE of 22.47%. Meanwhile, the stability of the modified device is effectively improved and the hysteresis effect is reduced. This work demonstrates a promising strategy for high-efficient and stable PSCs by optimizing interface contact and passivating interface defects.