Enhanced anchoring enables highly efficient and stable inverted perovskite solar cells

The immobilization of all-type ions is critical for further enhancing the efficiency and stability of inverted perovskite solar cells as the volatilization of organic cations and migration of halides could cause device degradation and non-radiative recombination. This work reports a novel and effective multidentate molecular "lock", 2,3,4,5,6-Pentafluorophenylammonium Iodide (F5PhAI), to simultaneously immobilize all types of ions in perovskite with multiple chemical anchoring sites, leading to enhanced stability of perovskite under thermal and ambient conditions, as well as reduced defect density and energy disorder of perovskite films to significantly inhibit the non-radiative recombination. As a result, F5PhAI-modified device achieves an improved PCE of 24.03%, with a VOC of 1.124 V, a JSC of 25.14 mA cm−2, and an FF of 85.03%. Furthermore, the unencapsulated devices exhibit enhanced long-term stability, maintaining 85% and 90% of the initial efficiencies under 85°C thermal annealing in nitrogen for 500 hours and in humid air condition (RH: 60±10%) for 1000 hours, respectively. This work provides a novel and effective multidentate molecular "lock" strategy to achieve high-efficiency and stable inverted perovskite solar cells.