Picolylamine Isomers Trigger Multidimension Coupling Strategy toward Efficient and Stable Inorganic Perovskite Solar Cells

Abstract

Although the CsPbI x Br3−x (0 ≤ x ≤ 3) inorganic perovskite has emerged as excellent candidate for advanced photovoltaic technologies, the long‐term stability against moisture is a detrimental issue that lags their power conversion efficiency (PCE). Herein, picolylamine isomers triggered multidimension coupling strategy is experimentally and theoretically proved to be capable of stabilizing black phase with hydrogen bonding and establishing new‐fangled charge carrier transport channel by means of the π–π stacking interaction between conjugating A‐site organic groups. Equally importantly, the presence of functional A‐site organic group stemming from electron‐rich benzene ring in 1D perovskite, i.e., 4‐picolylamine (4‐PA), is also able to passivate the iodine vacancy defect (VI) drifting in the 3D perovskite layer. Accordingly, the optimized CsPbI2.85Br0.15 perovskite solar cells (PSCs) allow to yield a PCE as high as 19.75% under AM1.5G light intensity, and the unencapsulated devices remain 94% of their original PCE after 3000 h aging upon 1.5 AM light irradiation with a relative humidity of 25%, exhibiting remarkable enhancement in comparison to their 3D counterparts. This study provides an in‐depth insight of the multidimension coupling strategy in developing state‐of‐the‐art inorganic PSCs.