Highly efficient planar perovskite solar cells via acid-assisted surface passivation†
Abstract
Low-temperature solution-processed SnO2-based perovskite solar cells (PSCs) have achieved great progress recently, but they still suffer from a critical drawback due to the defects at the SnO2/perovskite interface. Herein, we report a facile acetic acid post-treatment strategy to effectively passivate the surface defects. With an optimal concentration of acetic acid, the average power conversion efficiency (PCE) of the planar-type triple cation PSCs is greatly increased from 18.57% to 20.33%. The champion device shows a PCE of 20.56%. In addition, the universality of this passivation strategy is double confirmed by achieving an enhanced average PCE from 19.52% to 21.64% for sequential method deposited dual cation PSCs, with a leading PCE of 21.95%. Our work demonstrates an effective passivation strategy for SnO2-based planar-type PSCs, which will benefit the development of high-efficiency PSCs.