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

Abstract

AbstractNumerous 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 (PTCoPF6), is incorporated into the perovskite precursor solution to regulate crystallization and minimize holistic defects for high‐performance inverted PSCs. The cobaltocenium cations and PF6− in PTCoPF6 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 PTCoPF6 can passivate the deep‐level defects of uncoordinated lead. The interaction between PTCoPF6 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 PTCoPF6‐incorporated PSC achieves an impressive power conversion efficiency of 25.03% and outstanding long‐term stability. Unencapsulated and encapsulated PTCoPF6‐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.