Enhancing the Performance of Hole‐Conductor‐Free Printable Mesoscopic Perovskite Solar Cells through Polyaniline‐Mediated Iodine Recycling and Defect Passivation

Abstract Printable mesoscopic perovskite solar cells (p‐MPSCs) provide an opportunity for low‐cost manufacturing of photovoltaics. However, the performance of p‐MPSCs is severely compromised by iodine defects. This study presents a strategy by incorporating polyaniline (PANI) to achieve both iodine recycling and iodine defect passivation to significantly improve the performance of p‐MPSCs. PANI captures and immobilizes iodine ions, establishing a stable iodine recycling system that effectively suppresses iodine loss. Additionally, the Lewis base properties of PANI enable it to passivate iodine defects within the perovskite and suppress nonradiative recombination. With the synergistic effects, PANI increases the power conversion efficiency of the champion device from 18.28% to 20.24%. This strategy offers a potential solution for enhancing the performance of p‐MPSCs with promising implications for practical applications.