The poly(styrene-co-acrylonitrile) polymer assisted preparation of high-performance inverted perovskite solar cells with efficiency exceeding 22%

Solution treatment of perovskite films introduces many defects in the grain boundaries (GBs), which affects the power conversion efficiency (PCE) and long-term stability of the perovskite solar cells (PSCs). Designing suitable modification materials is the key to solving these problems. Herein, we synthesize the poly(styrene-co-acrylonitrile) polymer (PS-PAN polymer) through a facile polymerization method. The polymer successfully introduces nitrile (C≡N) into the PS chain and exhibits good thermal stability. When the PS-PAN polymer is added to the antisolvent to modify the perovskite film, it can passivate the GBs/surface defects and restrain the carrier recombination of the perovskite film. As a result, we obtain an enhanced PCE in inverted PSCs increasing from 18.18% to 22.02%. More importantly, the nonencapsulated PS-PAN-modified PSCs demonstrate good illumination and thermal stabilities and maintain 90% PCE under full-spectrum illumination at 75 °C in nitrogen glove box for 800 h. In addition, the designed device is resistant to moisture, retaining 91% PCE in air (50 ± 5% relative humidity) for 4000 h.