Synergistic Passivation by (Thiomorpholine-4-yl)methyl Potassium Trifluoroborate Enhances the Optoelectronic Performance of Perovskite Films

Perovskite solar cells (PSCs) hold the potential to surpass crystalline silicon cells in terms of cost, fabrication process, and ultimate efficiency. However, defects in the bulk and buried interfaces lead to carrier recombination centers and induce ion migration, severely limiting device efficiency and stability. In this study, we employed (thiomorpholine-4-yl)methyl trifluoroborate potassium (TMM-K) with multiple passivation sites to achieve synergistic passivation of the perovskite bulk and buried interfaces. This passivator not only improved the crystallinity of perovskite but also facilitated interfacial band alignment, enhancing charge extraction and suppressing interfacial recombination. As a result, the efficiency of PSCs increased from 21.22% to 22.67% on a 4 cm² area. Moreover, the hydrophobic nature of TMM-K significantly enhanced the stability of the perovskite films, providing valuable insights for the commercial development of PSCs.