Multifunctional Passivator Enables High-Efficient Gas-Quenching Sn–Pb Perovskite Solar Cells
Yibin Lai, Xuehui Xu, Xing Tang, Li Pan, Huiyan Chen, Hanbo Zhu, Ran Peng, Lurong Yang, Ziyan Jia, Juan Hui, Xiao‐Jian She, Ye Yuan, Yang Yang
Abstract
Tin–lead (Sn–Pb) perovskites deliver ideal bandgaps (∼1.25 eV) for both single-junction and tandem photovoltaics; however, their rapid crystallization kinetics and Sn 2+ oxidation vulnerability propagate severe defect densities that limit efficiency and stability. Herein, we design a multifunctional passivator, n -dodecylammonium acetate (DOAAc), in which acetate anions (Ac – ) simultaneously passivate halide vacancies and coordinate undercoordinated surface Pb 2+ /Sn 2+ sites. Consequently, DOAAc demonstrated superior passivation efficacy, enhanced interfacial binding strength, and exceptional oxidation resistance. XPS validation reveals that surface Sn 4+ content reduces from 24.41% to 8.62% with DOAAc treatment. Transient ion migration measurements further show a 4.5-fold reduction in mobile ion density, while XPS/FTIR analyses confirm robust complex-induced interfacial adhesion. UPS/SCLC/TRPL collectively verifies optimized energy-level alignment, reduced trap density, and enhanced carrier dynamics. Finally, DOAAc-passivated Sn–Pb PSCs achieve a record efficiency of 23.33% for gas-quenching fabricated devices. Under continuous AM 1.5G illumination (65 °C, xenon lamp), T 80 lifetime is extended by nearly 2-fold compared to the control devices.