Potassium Pentaminodifluorobenzoate-Modified SnO2 for Efficient and Stable Perovskite Solar Cells

Perovskite solar cells have rapidly developed into the standard representative of the third generation of photovoltaic power generation due to their low energy consumption and low cost. This device faces many challenges in achieving higher efficiency and better long-term stability. The core issue is the passivation of various defects and appropriate energy-level matching. Herein, the use of potassium pentaminodifluorobenzoate (KAFA) not only improves the light transmittance of SnO 2 /ITO, but also passivates the interface defects of SnO 2 /perovskite by introducing amino, carboxyl, fluorine, and potassium ions. This allows the device to form a suitable energy-level arrangement, thereby greatly improving the performance of perovskite solar cells. Compared with 20.36% of the pristine device, the KAFA-SnO 2 -based device achieves a champion power conversion efficiency of 22.46%, with an increase in short-circuit current from 23.94 to 24.78 mA cm −2 and open-circuit voltage from 1.149 to 1.169 V. After 120 h of continuous illumination with standard sunlight under N 2 atmosphere, its initial efficiency is still as high as 88.8%, showing excellent stability.