Anchoring CsPbI3 crystalline for stable and efficient perovskite solar cells with perfluorocarbon-assisted shield

The inorganic perovskite solar cells (PSCs) are now playing an increasingly essential role in the realm of clean energy. However, the application of inorganic perovskite solar cells is usually limited as the spontaneous phase transform. Here, we applied the 1H, 1H-Perfluorooctylammonium iodide (PFOAI) upon the surface of the cesium lead iodide (CsPbI3) films by taking advantage of its excellent defect passivation ability and hydrophobicity. Decreased recombination upon the surface and postponed degradation of the device were achieved for the observation of lower trap density and longer carrier lifetime and better stability based on the PFOAI-CsPbI3 films. The champion PFOAI-CsPbI3 based device showed an increased power conversion efficiency (PCE) of 18.24% with the excellent fill factor (FF) of 81.77% and Jsc of 20.51 mA cm(-2) and remain similar to 85% of its initial PCE for 1000 h (25 degrees C) in the N-2 glovebox. This work adds slightly weight on the balance of balancing the stability and high efficiency of the inorganic PSCs.