Ambient‐Air‐Stable Inverted Perovskite Solar Cells by Carbazole Analog Tailored Perovskite Thin Films

Perovskite solar cells (PSCs) have aroused vast attention and achieved unprecedented development. However, commercial utilization requires better reliability while maintaining high efficiency. Typically, the uncoordinated band energy configuration and structural defects led to recombination, these bottlenecks have seriously damaged the device performance and limited the further development of PSCs. In addressing those questions, researchers have provided various countermeasures including doping to trim the band structure and solvent engineering to modify the crystallization process and introducing reduced dimensional perovskite to maintain long‐term stability. Herein, a convenient carbazole analog doping strategy is reported by adding a certain amount of bromide‐substituted carbazole analog in the perovskite precursor which succeeded in modifying the surface morphology and optimizing the bandgap structure of the film, additionally maintaining considerable stability. As a result, a champion power conversion energy (PCE) of 22.25% is reached and preserved 85% of the initial PCE while stored in ambient air for more than 1200 h (around 30% relative humidity), and with low hysteresis. A simple but practical doping strategy to fabricate efficient and stable perovskite films in ambient air is provided.