Concurrent Perovskite Crystallization and Interface Modulation via Sulfonamides for High‐Performance Printable Mesoscopic Perovskite Solar Cells

Hole‐conductor‐free, printable mesoscopic perovskite solar cells with carbon electrodes present a viable strategy for industrial manufacturing of photovoltaics with low cost. However, depositing perovskite absorber within their intricate triple‐layer (TiO 2 /ZrO 2 /carbon) mesoporous scaffold makes it challenging to regulate the crystallization process, leading to limited crystal quality and high defect density of perovskite, resulting in performance loss. Moreover, the adopted TiO 2 electron transport layer (ETL) with insufficient electrical properties and high surface defect density restricts the carrier injection at the ETL/perovskite interface and exacerbates recombination loss. Herein, two sulfonamide additives, including sulfanilamide (SA) and sulfaguanidine (SG), are introduced into the perovskite precursor. Both additives present strong interaction capability with the key components, such as Pb 2+ and formamidinium (FA + ) of the halide perovskite, thus regulating the crystallization processes. Meanwhile, they passivate surface defects and enhance the electrical property of TiO 2 , thus promoting carrier injection at the ETL/perovskite interface. With their concurrent modulation in crystallization and interface, SA and SG improve the device power conversion efficiencies to 19.84% and 21.50% from 18.02%. Meanwhile, the better‐performing SG device retains 90% of its initial PCE after 530 h of maximum power point tracking at 55°C ± 5°C under 1‐sun illumination.