Tailoring Conjugated Imidazolium Additives Enables High‐Performance Inverted Perovskite Solar Cells via In Situ Forming Low‐Dimensional Perovskites

ABSTRACT Despite the exceptional optoelectronic properties of three‐dimensional (3D) perovskites, their commercial application remains constrained by insufficient long‐term stability. Low‐dimensional (LD)@3D perovskites integrate the high efficiency of 3D frameworks with the superior stability of LD phases, presenting a highly promising architecture. Herein, a series of aromatic heterocyclic imidazole derivatives, specifically 1H‐benzo[d]imidazole hydroiodide (BnI), 3H‐imidazo[4,5‐b]pyridine hydroiodide (PdI), and 1H‐imidazo[4,5‐b]pyrazine hydroiodide (PzI), are tailored and incorporated into perovskite precursors as additives, promoting the formation of LD@3D perovskites. The LD perovskites can effectively passivate defects at the grain boundary and interface, optimize energy level alignment, and improve hole extraction. As a result, the champion perovskite solar cells (PSCs) based on PzI achieve an excellent power conversion efficiency (PCE) of 25.63%. Meanwhile, the unencapsulated devices with PzI display superior long‐term stability, which retain 90% of their initial PCE after 1600 h in ambient air. Finally, this strategy is successfully scaled to minimodules, delivering an efficiency of 21.51% for an active area of 20.25 cm ² , which is a very competitive efficiency in minimodules. This study highlights the pivotal role of rational additive engineering in LD@3D perovskites, demonstrating that tailored molecular design for highly efficient and stable PSCs.