Multifunctional Dicarboxylic Acid Molecules Enable 19.61% Efficiency in Carbon-Based Printable Mesoscopic Perovskite Solar Cells

and thereby effectively suppressing nonradiative recombination. Meanwhile, FDCA formed strong interactions with the perovskite, effectively moderating its rapid crystallization and thereby promoting the dense filling and high-quality growth of the perovskite film in the triple-layer mesoscopic structure. Benefiting from the above synergistic effects of FDCA, the power conversion efficiency (PCE) of FDCA-modified p-MPSCs increased significantly from 18.17% to 19.61%. Furthermore, unencapsulated FDCA-modified devices retained over 90% of their initial PCE after being stored for 100 days in ambient air (25 ± 5 °C, 40 ± 5% RH), demonstrating excellent long-term stability.