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

Printable mesoscopic perovskite solar cells (p-MPSCs) present notable advantages, including simple fabrication, low cost, and scalability. However, the three-dimensional interpenetrating network of the triple-layer mesoscopic structure complicates the crystallization of perovskite and tends to introduce more defects. In this work, the multifunctional dicarboxylic acid molecule 2,5-furandicarboxylic acid (FDCA) was incorporated to regulate the crystallization process of perovskite within the triple-layer mesoscopic structure. The symmetrically arranged carboxyl groups in FDCA serve as Lewis bases, passivating undercoordinated Pb 2+ 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.