Synergistic Crystallization Kinetics Modulation and Deep/Shallow Level Defect Passivation via an Organometallic Cobaltocenium Salt Toward High‐Performance Inverted Perovskite Solar Cells

Abstract Numerous deep/shallow level defects generated at the surface/grain boundaries of perovskite during uncontrollable crystallization pose a formidable challenge to the photovoltaic performance of perovskite solar cells (PSCs). Herein, an organometallic cobaltocenium salt additive, 1‐propanol‐2‐(1,2,3‐triazol‐4‐yl) cobaltocenium hexafluorophosphate (PTCoPF 6 ), is incorporated into the perovskite precursor solution to regulate crystallization and minimize holistic defects for high‐performance inverted PSCs. The cobaltocenium cations and PF 6 − in PTCoPF 6 stabilize the Pb‐I framework and repair the shallow‐level defects of positively and negatively charged vacancies in the perovskite. The N═N in the triazole ring of PTCoPF 6 can passivate the deep‐level defects of uncoordinated lead. The interaction between PTCoPF 6 and perovskite materials delays perovskite nucleation and crystal growth, ensuring high‐quality perovskite with large grains, and suppressing non‐radiative recombination and ion migration. Therefore, the PTCoPF 6 ‐incorporated PSC achieves an impressive power conversion efficiency of 25.03% and outstanding long‐term stability. Unencapsulated and encapsulated PTCoPF 6 ‐incorporated PSCs maintain 93% and 95% of their initial efficiencies under 85 °C storage in a nitrogen atmosphere for 1000 h and maximum power point tracking for nearly 1000 h, respectively. Synergistic crystallization kinetic modulation and deep/shallow level defect passivation with ionized metal‐organic complex additives will become prevalent methods to improve the efficiency and stability of PSCs.