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

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 cm², 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.