Enhancing the Performance of Fa-Based Printable Mesoscopic Perovskite Solar Cells via the Polymer Additive

The low cost and scalability advantages of printable mesoscopic perovskite solar cells (p-MPSCs) are impaired by the issue of limited power conversion efficiency (PCE). Herein, the PCE of p-MPSCs is improved by introducing the polymer additive polyacrylonitrile (PAN) into the formamidinium (FA)-based perovskite for crystallization and defect modulation. PAN forms hydrogen bond and coordination bond with halide perovskite through its C≡N group. Such interactions improve the crystallization and filling of FA-based perovskite in the mesoscopic scaffold and bring a long carrier lifetime by passivating defects. The synergy improves the PCE of p-MPSCs from 16.80% to 18.33%. Meanwhile, the hydrophobic nature of PAN enhances the device's resistance against moisture. This work demonstrates that the polymer additive is a promising choice for breaking the PCE limit of p-MPSCs.